WorldWideScience

Sample records for aqueous two-phase system

  1. Separation of aqueous two-phase polymer systems in microgravity

    Science.gov (United States)

    Vanalstine, J. M.; Harris, J. M.; Synder, S.; Curreri, P. A.; Bamberger, S. B.; Brooks, D. E.

    1984-01-01

    Phase separation of polymer systems in microgravity is studied in aircraft flights to prepare shuttle experiments. Short duration (20 sec) experiments demonstrate that phase separation proceeds rapidly in low gravity despite appreciable phase viscosities and low liquid interfacial tensions (i.e., 50 cP, 10 micro N/m). Ostwald ripening does not appear to be a satisfactory model for the phase separation mechanism. Polymer coated surfaces are evaluated as a means to localize phases separated in low gravity. Contact angle measurements demonstrate that covalently coupling dextran or PEG to glass drastically alters the 1-g wall wetting behavior of the phases in dextran-PEG two phase systems.

  2. Electrostatic interactions and aqueous two-phase separation modes of aqueous mixed oppositely charged surfactants system.

    Science.gov (United States)

    Hao, Li-Sheng; Gui, Yuan-Xiang; Chen, Yan-Mei; He, Shao-Qing; Nan, Yan-Qing; You, Yi-Lan

    2012-08-30

    Electrostatic interactions play an important role in setting the aqueous two-phase separation behaviors of mixtures of oppositely charged surfactants. The aqueous mixture of cetyltrimethylammonium bromide (CTAB) and sodium dodecylsulfonate (AS) is actually a five-component system, comprised of CTAB, AS, complex salt (cetyltrimethylammonium dodecylsulfonate, abbreviated as CTA(+)AS(-)), NaBr, and water. In the three-dimensional pyramid phase diagram, the aqueous two-phase region with excess AS or with excess CTAB extends successively from the region very near to the NaBr-H2O line through the CTAB-AS-H2O conventional mixing plane to the CTA(+)AS(-)-AS-H2O side plane or to the CTA(+)AS(-)-CTAB-H2O side plane, respectively. Large or small molar ratios between the counterions and their corresponding surfactant ions for oppositely charged surfactants located in the NaBr side or the CTA(+)AS(-) side of the pyramid imply strong or weak electrostatic screening. Electrostatic screening of counterions alters the electrostatic attractions between the oppositely charged head groups or the electrostatic repulsions between the like-charged head groups in excess, and the electrostatic free energy of aggregation thus affects the aqueous two-phase separation modes. Composition analysis, rheological property investigation, and TEM images suggest that there are two kinds of aqueous two-phase systems (ATPSs). On the basis of these experimental results and Kaler's cell model, two kinds of phase separation modes were proposed. Experimental results also indicate that all of the top phases are surfactant-rich, and all of the bottom phases are surfactant-poor; the density difference between the top phase and the bottom phase in one ATPS is very small; the interfacial tension (σ) of the ATPS is ultralow. PMID:22856887

  3. Two-phase aqueous micellar systems: an alternative method for protein purification

    Directory of Open Access Journals (Sweden)

    Rangel-Yagui C. O.

    2004-01-01

    Full Text Available Two-phase aqueous micellar systems can be exploited in separation science for the extraction/purification of desired biomolecules. This article reviews recent experimental and theoretical work by Blankschtein and co-workers on the use of two-phase aqueous micellar systems for the separation of hydrophilic proteins. The experimental partitioning behavior of the enzyme glucose-6-phosphate dehydrogenase (G6PD in two-phase aqueous micellar systems is also reviewed and new results are presented. Specifically, we discuss very recent work on the purification of G6PD using: i a two-phase aqueous micellar system composed of the nonionic surfactant n-decyl tetra(ethylene oxide (C10E4, and (ii a two-phase aqueous mixed micellar system composed of C10E4 and the cationic surfactant decyltrimethylammonium bromide (C10TAB. Our results indicate that the two-phase aqueous mixed (C10E4/C10TAB micellar system can improve significantly the partitioning behavior of G6PD relative to that observed in the two-phase aqueous C10E4 micellar system.

  4. The Effect of pH Difference Between Two Phases on the Partition of Lysozyme in Aqueous Two-Phase System

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In the investigation of effect of KSCN on the partitioning of lysozyme in PEG2000/ammonium sulfate aqueous two-phase system, it was found that the KSCN could alter the pH difference between the two phases, and thus affect the partition of lysozyme. The relationship between partition coefficients of lysozyme and pH differences between two phases was discussed.

  5. Extraction of peptide tagged cutinase in detergent-based aqueous two-phase systems

    NARCIS (Netherlands)

    Rodenbrock, A.; Selber, K.; Egmond, M.R.; Kula, M.-R.

    2010-01-01

    Detergent-based aqueous two-phase systems have the advantage to require only one auxiliary chemical to induce phase separation above the cloud point. In a systematic study the efficiency of tryptophan-rich peptide tags was investigated to enhance the partitioning of an enzyme to the detergent-rich p

  6. Rapid RNA Exchange in Aqueous Two-Phase System and Coacervate Droplets

    OpenAIRE

    Jia, Tony Z.; Hentrich, Christian; SZOSTAK, JACK W.

    2014-01-01

    Compartmentalization in a prebiotic setting is an important aspect of early cell formation and is crucial for the development of an artificial protocell system that effectively couples genotype and phenotype. Aqueous two-phase systems (ATPSs) and complex coacervates are phase separation phenomena that lead to the selective partitioning of biomolecules and have recently been proposed as membrane-free protocell models. We show in this study through fluorescence recovery after photobleaching (FR...

  7. On-chip aqueous two-phase system (ATPS) formation, consequential self-mixing, and their influence on drop-to-drop aqueous two-phase extraction kinetics

    Science.gov (United States)

    Wijethunga, Pavithra A. L.; Moon, Hyejin

    2015-09-01

    Aqueous two-phase systems (ATPSs) allow an advantageous aqueous two-phase extraction process (ATPE), a special type of liquid-liquid extraction. Compared with conventional liquid-liquid extraction using aqueous/organic extraction media, ATPE is known to provide relatively easy mass transfer and a gentle environment for biological separation applications. Considering the recent interest in microscale ATPE, we aimed to study (i) the potential of preparing ATPS droplets on a digital microfluidic device, and (ii) the influence of the fluidic dynamics created during the formation of ATPS, with the goal of enhancing on-chip ATPE process. On-chip ATPS formation was evaluated by preparing a series of ATPSs on electrowetting on dielectric digital microfluidic chips and comparing their characteristics with the same ATPSs prepared at macroscale using conventional procedures. An enhanced on-chip drop-to-drop ATPE process was achieved by incorporating a self-mixing condition created during ATPSformation. Results indicate a successful on-chip ATPS preparation as well as enhanced extraction performance by self-mixing in the absence of forced mixing. Findings of this research suggest an alternative, simple, yet adequate technique to provide mixing for on-chip applications, such as sample preparation in portable microfluidics, for which it is unfavorable to implement complicated mixing sequences or complex device geometries.

  8. Selective separation and enrichment of proteins in aqueous two-phase extraction system

    Institute of Scientific and Technical Information of China (English)

    Feng Qu; Hao Qin; Min Dong; Dong Xu Zhao; Xin Ying Zhao; Jing Hua Zhang

    2009-01-01

    A simple aqueous two-phase extraction system(ATPS)of PEG/phosphate was proposed for selective separation and enrichment of proteins.The combination of ATPE with HPLC was applied to identify the partition of proteins in two phases.Five proteins (bovine serum albumin,Cytochrome C,lysozyme,myoglobin,and trypsin)were used as model proteins to study the effect of phosphate concentration and pH on proteins partition.The PEG/phosphate system was firstly applied to real human saliva and plasma samples,some proteins showed obviously different partition in two phases.The primary results manifest the selective separation and enrichment of proteins in ATPS provided the potential for high abundance proteins depletion in proteomics.

  9. Partitioning Behavior of Papain in Ionic Liquids-Based Aqueous Two-Phase Systems

    OpenAIRE

    Zhiwen Bai; Yanhong Chao; Meiling Zhang; Changri Han; Wenshuai Zhu; Yonghui Chang; Huaming Li; Yang Sun

    2013-01-01

    This paper attempts to study and optimize the affinity partitioning conditions of papain in an aqueous two-phase system (ATPS). The effect of the amount of ionic liquids (ILs), the concentration of K2HPO4, temperature, pH, and the volume of papain solution were discussed concretely. The optimum conditions were determined as ionic liquid was 1.4 g and K2HPO4 was 1.4 g, the extraction efficiency of papain co...

  10. Drowning-out crystallisation of sodium sulphate using aqueous two-phase systems.

    Science.gov (United States)

    Taboada, M E; Graber, T A; Asenjo, J A; Andrews, B A

    2000-06-23

    A novel method to obtain crystals of pure, anhydrous salt, using aqueous two-phase systems was studied. A concentrated salt solution is mixed with polyethylene glycol (PEG), upon which three phases are formed: salt crystals, a PEG-rich liquid and a salt-rich liquid. After removal of the solid salt, a two-phase system is obtained. Both liquid phases are recycled, allowing the design of a continuous process, which could be exploited industrially. The phase diagram of the system water-Na2SO4-PEG 3350 at 28 degrees C was used. Several process alternatives are proposed and their economic potential is discussed. The process steps needed to produce sodium sulphate crystals include mixing, crystallisation, settling and, optionally, evaporation of water. The yield of sodium sulphate increases dramatically if an evaporation step is used. PMID:10942277

  11. A stable liquid–liquid extraction system for clavulanic acid using polymer-based aqueous two-phase systems

    OpenAIRE

    Pereira, Jorge F. B.; Santos, Valéria Carvalho; Johansson, Hans-Olof; J. A. Teixeira; Pessoa Júnior, Adalberto

    2012-01-01

    The partitioning of Clavulanic Acid (CA) in a novel inexpensive and stable aqueous two-phase system (ATPS) composed by poly(ethylene glycol) (PEG) and sodium polyacrylate (NaPA) has been studied. The aqueous two-phase systems are formed by mixing both polymers with a salt (NaCl or Na2SO4) and an aqueous solution of CA. The stability of CA on the presence of both polymers was investigated and it was observed that these polymers do not degrade the biomolecule. The effect of PEG-molecular ...

  12. Rapid RNA Exchange in Aqueous Two-Phase System and Coacervate Droplets

    Science.gov (United States)

    Jia, Tony Z.; Hentrich, Christian; Szostak, Jack W.

    2014-02-01

    Compartmentalization in a prebiotic setting is an important aspect of early cell formation and is crucial for the development of an artificial protocell system that effectively couples genotype and phenotype. Aqueous two-phase systems (ATPSs) and complex coacervates are phase separation phenomena that lead to the selective partitioning of biomolecules and have recently been proposed as membrane-free protocell models. We show in this study through fluorescence recovery after photobleaching (FRAP) microscopy that despite the ability of such systems to effectively concentrate RNA, there is a high rate of RNA exchange between phases in dextran/polyethylene glycol ATPS and ATP/poly-L-lysine coacervate droplets. In contrast to fatty acid vesicles, these systems would not allow effective segregation and consequent evolution of RNA, thus rendering these systems ineffective as model protocells.

  13. Selective separation of protein and saccharides by ionic liquids aqueous two-phase systems

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    In the present work,it was found that aqueous solution of a hydrophilic ionic liquid (IL),1-butyl-3-methylimidazolium dicyanamide ([C4mim][N(CN)2]),could be separated into an aqueous two-phase system (ATPS) by inorganic salts such as K2HPO4 and K3PO4.The top phase is IL-rich,while the bottom phase is phosphate-rich.It was shown that 82.7%-100% bovine serum albumin (BSA) could be enriched into the top phase and almost quantitative saccharides (arabinose,glucose,sucrose,raffinose or dextran) were preferentially extracted into the bottom phase in a single-step extraction by [C4mim][N(CN)2] + K2HPO4 ATPS.The extraction efficiency of BSA from the aqueous saccharide solutions was influenced by the molecular structure of saccharides.The conductivity,dynamic light scattering (DLS) and transmission electron microscopy (TEM) were combined to investigate the microstructure of the IL-rich top phase and the possible mechanism for the selective separation.It is suggested that the formation of the IL aggregate and the IL aggregate-BSA complex plays a significant role in the separation of BSA from aqueous saccharide solutions.This is the first example for the selective separation by ILs-based ATPSs.It is expected that these findings would have potential applications in bio-analysis,separation,and IL recycle.

  14. Stability of clavulanic acid in PEG/citrate and liquid–liquid extraction in aqueous two-phase system

    OpenAIRE

    Carneiro-da-Cunha, M. N.; Souza, K. P. S.; Mota, A; J.A. Teixeira; Porto, C S; Porto, Tatiana Souza; Porto, Ana L. F.

    2014-01-01

    β-Lactamases are enzymes responsible for the hydrolysis of β-lactam antibiotics, being produced by several pathogenic bacteria. Clavulanic acid is a commercially and clinically important β-lactamase inhibitor, its extraction being possible by the application of aqueous two-phase system. In this study, clavulanic acid stability was investigated at different molar mass PEG (400, 1 000 and 20 000 g mol−1) and at different citrate concentrations (5 and 20%) PEG/citrate aqueous-two phase systems (...

  15. Protein partitioning in poly(ethylene glycol)/sodium polyacrylate aqueous two-phase systems.

    Science.gov (United States)

    Johansson, Hans-Olof; Magaldi, Flavio Musa; Feitosa, Eloi; Pessoa, Adalberto

    2008-01-18

    The partition of hemoglobin, lysozyme and glucose-6-phosphate dehydrogenase (G6PDH) in a novel inexpensive aqueous two-phase system (ATPS) composed by poly(ethylene glycol) (PEG) and sodium polyacrylate (NaPA) has been studied. The effect of NaCl and Na(2)SO(4), pH and PEG molecular size on the partitioning has been studied. At high pH (above 9), hemoglobin partitions strongly to the PEG-phase. Although some precipitation of hemoglobin occurs, high recovery values are obtained particularly for lysozyme and G6PDH. The partitioning forces are dominated by the hydrophobic and electrochemical (salt) effects, since the positively charged lysozyme and negatively charged G6PDH partitions to the non-charged PEG and the strongly negatively charged polyacrylate enriched phase, respectively. PMID:18078945

  16. Ionic Liquid-salt Aqueous Two-phase System, a Novel System for the Extraction of Abused Drugs

    Institute of Scientific and Technical Information of China (English)

    She Hong LI; Chi Yang HE; Hu Wei LIU; Ke An LI; Feng LIU

    2005-01-01

    A 1-butyl-3-methylimidazolium chloride-salt aqueous two-phase system was studied on extraction of abused drugs. The effects of sorts of salts, temperature, concentration of salt and drugs on system were investigated systematically. A satisfactory extraction efficiency of 93%was obtained for papaverine while that of morphine was 65%. The extraction mechanism was primarily discussed.

  17. A green deep eutectic solvent-based aqueous two-phase system for protein extracting

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Kaijia; Wang, Yuzhi, E-mail: wyzss@hnu.edu.cn; Huang, Yanhua; Li, Na; Wen, Qian

    2015-03-15

    Highlights: • A strategy for the protein purification with a deep eutectic solvent(DES)-based aqueous two-phase system. • Choline chloride-glycerin DES was selected as the extraction solvent. • Bovine serum albumin and trypsin were used as the analytes. • Aggregation phenomenon was detected in the mechanism research. - Abstract: As a new type of green solvent, deep eutectic solvent (DES) has been applied for the extraction of proteins with an aqueous two-phase system (ATPS) in this work. Four kinds of choline chloride (ChCl)-based DESs were synthesized to extract bovine serum albumin (BSA), and ChCl-glycerol was selected as the suitable extraction solvent. Single factor experiments have been done to investigate the effects of the extraction process, including the amount of DES, the concentration of salt, the mass of protein, the shaking time, the temperature and PH value. Experimental results show 98.16% of the BSA could be extracted into the DES-rich phase in a single-step extraction under the optimized conditions. A high extraction efficiency of 94.36% was achieved, while the conditions were applied to the extraction of trypsin (Try). Precision, repeatability and stability experiments were studied and the relative standard deviations (RSD) of the extraction efficiency were 0.4246% (n = 3), 1.6057% (n = 3) and 1.6132% (n = 3), respectively. Conformation of BSA was not changed during the extraction process according to the investigation of UV–vis spectra, FT-IR spectra and CD spectra of BSA. The conductivity, dynamic light scattering (DLS) and transmission electron microscopy (TEM) were used to explore the mechanism of the extraction. It turned out that the formation of DES–protein aggregates play a significant role in the separation process. All the results suggest that ChCl-based DES-ATPS are supposed to have the potential to provide new possibilities in the separation of proteins.

  18. A green deep eutectic solvent-based aqueous two-phase system for protein extracting

    International Nuclear Information System (INIS)

    Highlights: • A strategy for the protein purification with a deep eutectic solvent(DES)-based aqueous two-phase system. • Choline chloride-glycerin DES was selected as the extraction solvent. • Bovine serum albumin and trypsin were used as the analytes. • Aggregation phenomenon was detected in the mechanism research. - Abstract: As a new type of green solvent, deep eutectic solvent (DES) has been applied for the extraction of proteins with an aqueous two-phase system (ATPS) in this work. Four kinds of choline chloride (ChCl)-based DESs were synthesized to extract bovine serum albumin (BSA), and ChCl-glycerol was selected as the suitable extraction solvent. Single factor experiments have been done to investigate the effects of the extraction process, including the amount of DES, the concentration of salt, the mass of protein, the shaking time, the temperature and PH value. Experimental results show 98.16% of the BSA could be extracted into the DES-rich phase in a single-step extraction under the optimized conditions. A high extraction efficiency of 94.36% was achieved, while the conditions were applied to the extraction of trypsin (Try). Precision, repeatability and stability experiments were studied and the relative standard deviations (RSD) of the extraction efficiency were 0.4246% (n = 3), 1.6057% (n = 3) and 1.6132% (n = 3), respectively. Conformation of BSA was not changed during the extraction process according to the investigation of UV–vis spectra, FT-IR spectra and CD spectra of BSA. The conductivity, dynamic light scattering (DLS) and transmission electron microscopy (TEM) were used to explore the mechanism of the extraction. It turned out that the formation of DES–protein aggregates play a significant role in the separation process. All the results suggest that ChCl-based DES-ATPS are supposed to have the potential to provide new possibilities in the separation of proteins

  19. Effective extraction of elastase from Bacillus sp. fermentation broth using aqueous two-phase system

    Institute of Scientific and Technical Information of China (English)

    XU Ying; HE Guo-qing; LI Jing-jun

    2005-01-01

    This paper presents the evaluation of an aqueous two-phase system (ATPS) for extracting elastase produced by Bacillus sp. EL31410. The elastase and cell partition behavior in polyethylene glycol (PEG)/salt systems was investigated. The suitable system for elastase extraction was PEG/KH2PO4-K2HPO4, in which elastase is mainly partitioned into the PEG-rich phase,while the cells remained in the other phase. The influence of defined system parameters (e.g. PEG molecular mass, pH, NaCl addition) on the partitioning behavior of elastase is described. The concentration of phase forming components, PEG and KH2PO4-K2HPO4, was optimized for elastase recovery by means of response surface methodology, and it was found that they greatly influenced extraction recovery. The optimal ATPS was 23.1% (w/w) PEG 2 000 and 11.7% (w/w) KH2PO4-K2HPO4. The predicted recovery was about 89.5%, so this process is suggested to be a rapid and convenient method for elastase extraction.

  20. Aqueous Two-phase Systems with Ultrasonic Extraction Used for Extracting Phenolic Compounds from Inonotus obliquus

    Institute of Scientific and Technical Information of China (English)

    ZHAO; Yan-xia; LIU; Yu-bing; LIU; Feng; ZHENG; Wei-fa

    2013-01-01

    Objective To optimize the extracting technology of assessing the maximum yield of phenolic compounds (PC) from Inonotus obliquus by single factor experiments and orthogonal array design methods through aqueous two-phase systems combined with ultrasonic extraction. Methods The range of the independent variables, namely levels of acetone and ammonium sulfate, and ultrasonic time were identified by a first set of single factor experiments. The actual values of the independent variables coded at four levels and three factors were selected based on the results of the single factor experiments. Subsequently, the levels of acetone and ammonium sulfate, and ultrasonic time were optimized using the orthogonal array method. Results The optimum conditions for the extraction of PC were found to use 7.0 mL acetone, 5.5 mg ammonium sulfate, with ultrasonic time for 5 min. Under these optimized conditions, the experimental maximum yield of PC was 37.8 mg/g, much higher than that of the traditional ultrasonic extraction (UE, 29.0 mg/g). And the PC obtained by this method had stronger anti-oxidative activities than those by traditional UE method. Conclusion These results indicate the suitability of the models developed and the success in optimizing the extraction conditions. This is an economical and efficient method for extracting polyphenols from I. obliquus.

  1. Aqueous two phase system based on ionic liquid for isolation of quinine from human plasma sample.

    Science.gov (United States)

    Flieger, J; Czajkowska-Żelazko, A

    2015-01-01

    Aqueous two phase system was applied for selective extraction of quinine from human plasma. Bi-phase was constructed from ionic liquid: butyl-methyl-imidazolium chloride after addition kosmotropic salts K₃PO₄ or KH₂PO₄. Quinine was determined in plasma samples after drinking of tonic containing quinine. Determination was performed by HPLC on 5-μm Zorbax SB-CN column and eluent containing 40% acetonitrile (v/v), 20 mM phosphate buffer at pH 3 and 40 mM NaPF₆ using external standard method. The spectrophotometric detection was set λ=214 nm. Selective fluorescence detection was performed at excitation of 325 nm and emission of 375 nm. Proposed strategy provides suitable sample purification and gives extraction yields in the range of 89-106%. The determination coefficient (R(2)) has a value ≥0.997 in the range of 50-800 ng/ml quinine concentration. The limit of quantification was set at 27.9 ng/ml and the detection limit was found to be 8.4 ng/ml under fluorescence detection.

  2. Aqueous Two-phase Systems with Ultrasonic Extraction Used for Extracting Phenolic Compounds from Inonotus obliquus

    Institute of Scientific and Technical Information of China (English)

    ZHAO Yan-xia; LIU Yu-bing; LIU Feng; ZHENG Wei-fa

    2013-01-01

    Objective To optimize the extracting technology of assessing the maximum yield of phenolic compounds (PC)from Inonotus obliquus by single factor experiments and orthogonal array design methods through aqueous two-phase systems combined with ultrasonic extraction.Methods The range of the independent variables,namely levels of acetone and ammonium sulfate,and ultrasonic time were identified by a first set of single factor experiments.The actual values of the independent variables coded at four levels and three factors were selected based on the results of the single factor experiments.Subsequently,the levels of acetone and ammonium sulfate,and ultrasonic time were optimized using the orthogonal array method.Results The optimum conditions for the extraction of PC were found to use 7.0 mL acetone,5.5 mg ammonium sulfate,with ultrasonic time for 5 min.Under these optimized conditions,the experimental maximum yield of PC was 37.8 mg/g,much higher than that of the traditional ultrasonic extraction (UE,29.0 mg/g).And the PC obtained by this method had stronger anti-oxidative activities than those by traditional UE method.Conclusion These results indicate the suitability of the models developed and the success in optimizing the extraction conditions.This is an economical and efficient method for extracting polyphenols from Ⅰ.obliquus.

  3. Aqueous two-phase systems strategies to establish novel bioprocesses for stem cells recovery.

    Science.gov (United States)

    González-González, Mirna; Rito-Palomares, Marco

    2014-12-01

    During the past decade, stem cell transplantation has emerged as a novel therapeutic alternative for several diseases. Nevertheless, numerous challenges regarding the recovery and purification steps must be addressed to supply the number of cells required and in the degree of purity needed for clinical treatments. Currently, there is a wide range of methodologies available for stem cells isolation. Nevertheless, there is not a golden standard method that accomplishes all requirements. A desirable recovery method for stem cells has to guarantee high purity and should be sensitive, rapid, quantitative, scalable, non- or minimally invasive to preserve viability and differentiation capacity of the purified cells. In this context, aqueous two-phase systems (ATPS) represent a promising alternative to fulfill the mentioned requirements, promoting the use of stem cell-based therapies for incurable diseases. This practical review focuses on presenting the bases for the development of a novel and scalable bioprocess for the purification of stem cells, with a case scenario of CD133(+) cells. The bioengineering strategies include the application of immunoaffinity ATPS in its multiple variants, including antibody-polymer conjugation, antibody addition and antibody immobilization. Conclusions are drawn in the light of the potential generic implementation of these strategies as an initial step in the establishment of bioprocesses for the purification of stem cells.

  4. Partitioning in aqueous two-phase systems: Analysis of strengths, weaknesses, opportunities and threats.

    Science.gov (United States)

    Soares, Ruben R G; Azevedo, Ana M; Van Alstine, James M; Aires-Barros, M Raquel

    2015-08-01

    For half a century aqueous two-phase systems (ATPSs) have been applied for the extraction and purification of biomolecules. In spite of their simplicity, selectivity, and relatively low cost they have not been significantly employed for industrial scale bioprocessing. Recently their ability to be readily scaled and interface easily in single-use, flexible biomanufacturing has led to industrial re-evaluation of ATPSs. The purpose of this review is to perform a SWOT analysis that includes a discussion of: (i) strengths of ATPS partitioning as an effective and simple platform for biomolecule purification; (ii) weaknesses of ATPS partitioning in regard to intrinsic problems and possible solutions; (iii) opportunities related to biotechnological challenges that ATPS partitioning may solve; and (iv) threats related to alternative techniques that may compete with ATPS in performance, economic benefits, scale up and reliability. This approach provides insight into the current status of ATPS as a bioprocessing technique and it can be concluded that most of the perceived weakness towards industrial implementation have now been largely overcome, thus paving the way for opportunities in fermentation feed clarification, integration in multi-stage operations and in single-step purification processes. PMID:26213222

  5. Partitioning in aqueous two-phase systems: Analysis of strengths, weaknesses, opportunities and threats.

    Science.gov (United States)

    Soares, Ruben R G; Azevedo, Ana M; Van Alstine, James M; Aires-Barros, M Raquel

    2015-08-01

    For half a century aqueous two-phase systems (ATPSs) have been applied for the extraction and purification of biomolecules. In spite of their simplicity, selectivity, and relatively low cost they have not been significantly employed for industrial scale bioprocessing. Recently their ability to be readily scaled and interface easily in single-use, flexible biomanufacturing has led to industrial re-evaluation of ATPSs. The purpose of this review is to perform a SWOT analysis that includes a discussion of: (i) strengths of ATPS partitioning as an effective and simple platform for biomolecule purification; (ii) weaknesses of ATPS partitioning in regard to intrinsic problems and possible solutions; (iii) opportunities related to biotechnological challenges that ATPS partitioning may solve; and (iv) threats related to alternative techniques that may compete with ATPS in performance, economic benefits, scale up and reliability. This approach provides insight into the current status of ATPS as a bioprocessing technique and it can be concluded that most of the perceived weakness towards industrial implementation have now been largely overcome, thus paving the way for opportunities in fermentation feed clarification, integration in multi-stage operations and in single-step purification processes.

  6. Measurement and Correlation of Equilibrium Data for Aqueous Two-phase System Ethanol+Water+K2HPO4

    Institute of Scientific and Technical Information of China (English)

    LIN Jin-qing; TAN Ping-hua; JIN Chun-ying; LI Ming-chun

    2004-01-01

    The isothermal solubility data of aqueous two-phase system ethanol+water+K2HPO4 were determined with the turbidity titration method at 303.2 K. The binodal curves were described by using the Mistry equation very well. An experimental procedure for measuring the liquid-liquid equilibrium data of the aqueous two-phase system was proposed, in which the concentrations of the coexisting phases were determined with the corresponding densities of the solution. The tie lines were satisfactorily described by using the Othmer Tobias and Bancroft equations.

  7. Purification of C-phycocyanin from Spirulina platensis in aqueous two-phase systems using an experimental design

    OpenAIRE

    Francine Silva Antelo; Jorge Alberto Vieira Costa; Susana Juliano Kalil

    2015-01-01

    C-phycocyanin from Spirulina platensis was purified in aqueous two-phase systems (ATPS) of polyethylene glycol (PEG)/potassium phosphate, varying the molar mass of the PEG. Results using a full factorial design showed that an increase in the concentration of salt and decrease in the concentration of PEG caused an increment in the purification factor for all the ATPS studied. Optimization of the conditions of the purification was studied using a central composite rotatable design for each mola...

  8. Aqueous two-phase micellar systems in an oscillatory flow micro-reactor: Study of perspectives and experimental performance

    OpenAIRE

    A. M. LOPES; Silva, Daniel Pereira da; A.A. Vicente; Pessoa Júnior, Adalberto; Teixeira, J. A.

    2011-01-01

    Aqueous two-phase micellar systems (ATPMS) are micellar surfactant solutions with physical properties that make them very efficient for the extraction/concentration of biological products. In this work the main proposal that has been discussed is the possible applicability and importance of a novel oscillatory flow micro-reactor (micro-OFR) envisaged for parallel screening and/or development of industrial bioprocesses in ATPMS. Based on the technology of oscillatory flow mixing (OFM), this ba...

  9. Partition of Chiral pharmaceutical intermediate R(-)-Mandelic Acid in Aqueous Two-Phase System of Poly(ethylene glycol)-Ammonium Sulfate

    Institute of Scientific and Technical Information of China (English)

    Xu Xiaoping; Li Zhongqin; Chen Jiebo; Huang Xinghua

    2004-01-01

    An aqueous two-phase system of poly (ethylene glycol)-ammonium sulfate was employed to separate R (-)-mandelic acid.The result showed that R (-)-mandelic acid has priority to partition in PEG-rich top phase. This indicated that aqueous two-phase is a very suitable system for separation of R(-)-mandelic acid.

  10. Phase Separation Behavior and System Properties of Aqueous Two-Phase Systems with Polyethylene Glycol and Different Salts: Experiment and Correlation

    OpenAIRE

    Haihua Yuan; Yang Liu; Wanqian Wei; Yongjie Zhao

    2015-01-01

    The phase separation behaviors of PEG1000/sodium citrate, PEG4000/sodium citrate, PEG1000/ammonium sulfate, and PEG4000/ammonium sulfate aqueous two-phase systems were investigated, respectively. There are two distinct situations for the phase separation rate in the investigated aqueous two-phase systems: one state is top-continuous phase with slow phase separation rate and strong bottom-continuous phase with fast phase separation rate and weak volume ratio dependence. The system properties s...

  11. A resolution approach of racemic phenylalanine with aqueous two-phase systems of chiral tropine ionic liquids.

    Science.gov (United States)

    Wu, Haoran; Yao, Shun; Qian, Guofei; Yao, Tian; Song, Hang

    2015-10-30

    Aqueous two-phase systems (ATPS) based on tropine type chiral ionic liquids and inorganic salt solution were designed and prepared for the enantiomeric separation of racemic phenylalanine. The phase behavior of IL-based ATPS was comprehensive investigated, and phase equilibrium data were correlated by Merchuk equation. Various factors were also systematically investigated for their influence on separation efficiency. Under the appropriate conditions (0.13g/g [C8Tropine]pro, 35mg/g Cu(Ac)2, 20mg/g d,l-phenylalanine, 0.51g/g H2O and 0.30g/g K2HPO4), the enantiomeric excess value of phenylalanine in solid phase (mainly containing l-enantiomer) was 65%. Finally, the interaction mechanism was studied via 1D and 2D NMR. The results indicate that d-enantiomer of phenylalanine interacts more strongly with chiral ILs and Cu(2+) based on the chiral ion-pairs space coordination mechanism, which makes it tend to remain in the top IL-rich phase. By contrast, l-enantiomer is transferred into the solid phase. Above chiral ionic liquids aqueous two-phase systems have demonstrated obvious resolution to racemic phenylalanine and could be promising alterative resolution approach for racemic amino acids in aqueous circumstance.

  12. Thermodynamic modelling of phase equilibrium for water + poly(Ethylene glycol + salt aqueous two-phase systems

    Directory of Open Access Journals (Sweden)

    R.A.G. Sé

    2002-04-01

    Full Text Available The NRTL (nonrandom, two-liquid model, expressed in mass fraction instead of mole fraction, was used to correlate liquid-liquid equilibria for aqueous two-phase polymer-salt solutions. New interaction energy parameters for this model were determined using reported data on the water + poly(ethylene glycol + salt systems, with different molecular masses for PEG and the salts potassium phosphate, sodium sulfate, sodium carbonate and magnesium sulfate. The correlation of liquid-liquid equilibrium is quite satisfactory.

  13. Phase Diagrams of the Aqueous Two-Phase Systems of Poly(ethylene glycol)/Sodium Polyacrylate/Salts

    OpenAIRE

    Adalberto Pessoa Junior; Hans-Olof Johansson; Eloi Feitosa

    2011-01-01

    Aqueous two-phase systems consisting of polyethylene glycol (PEG), sodium polyacrylate (NaPAA), and a salt have been studied. The effects of the polymer size, salt type (NaCl, Na2SO4, sodium adipate and sodium azelate) and salt concentrations on the position of the binodal curve were investigated. The investigated PEG molecules had a molar mass of 2,000 to 8,000 g/mol, while that of NaPAA was 8,000 g/mol. Experimental phase diagrams, and tie lines and calculated phase diagrams, based on Flory...

  14. Studies of efficiency in a perforated rotating disc contactor using a polymer-polymer aqueous two-phase systems

    Directory of Open Access Journals (Sweden)

    L. A. Sarubbo

    2005-09-01

    Full Text Available The mass transfer process in a perforated rotating disc contactor (PRDC using a polymer-polymer aqueous two-phase system was investigated. The results show that the efficiency did not show a regular trend with the increase of the dispersed phase velocity and increased with the rotation velocity. The separation efficiency was higher for three rotating discs than for four discs. The increase in tie-line length decreased the efficiency. The separation efficiency reached high values, about 96% under conditions studied in this work.

  15. Partition of volatile compounds in pea globulin-maltodextrin aqueous two-phase system.

    Science.gov (United States)

    Nguyen, Thanh Dat; Lafarge, Céline; Murat, Chloé; Mession, Jean-Luc; Cayot, Nathalie; Saurel, Rémi

    2014-12-01

    This study is based on the assumption that the off-flavour of pea proteins might be decreased using the retention of volatile compounds by a mixture with another biopolymer. The partition of volatile compounds in an aqueous system containing pea protein and maltodextrins was followed under thermodynamic incompatibility conditions. Firstly, the phase diagram of the system was established. Then, the partition of aroma compounds between the phase rich in protein and the phase rich in maltodextrin was measured by SPME-GC-MS. There was a transfer of volatile compounds during phase separation. Variations of pH were also used to vary the retention of volatile compounds by proteins. The concentration of volatile compounds in protein solution at pH 2.4 was higher than at pH 7.2. It was possible to increase the transfer of volatile compounds from the phase rich in protein to the phase rich in maltodextrin using the effect of pH on protein denaturation.

  16. Study on aqueous two-phase systems of the mixture SDS/CTAB surfactants

    Institute of Scientific and Technical Information of China (English)

    LI Ying; CHEN Yah-ming; ZHAO Kong-shuang; Takumi HIKIDA

    2004-01-01

    The phenomenon of two dilute aqueous phases composed of sodium dodecylsulfate (SDS) and cetyltrimethyl ammonium bromide(CTAB) was investigated under various conditions such as concentrations and molarratios of the two surfactants, the addition of sodium chloride and temperature. Vesicles formation was found in theboth phases by TEM image.

  17. Aqueous two-phase systems: an efficient, environmentally safe and economically viable method for purification of natural dye carmine.

    Science.gov (United States)

    Mageste, Aparecida Barbosa; de Lemos, Leandro Rodrigues; Ferreira, Guilherme Max Dias; da Silva, Maria do Carmo Hespanhol; da Silva, Luis Henrique Mendes; Bonomo, Renata Cristina Ferreira; Minim, Luis Antonio

    2009-11-01

    Partition of the natural dye carmine has been studied in aqueous two-phase systems prepared by mixing aqueous solutions of polymer or copolymer with aqueous salt solutions (Na(2)SO(4) and Li(2)SO(4)). The carmine dye partition coefficient was investigated as a function of system pH, polymer molar mass, hydrophobicity, system tie-line length and nature of the electrolyte. It has been observed that the carmine partition coefficient is highly dependent on the electrolyte nature and pH of the system, reaching values as high as 300, indicating the high potential of the two-phase extraction with ATPS in the purification of carmine dye. The partition relative order was Li(2)SO(4)"Na(2)SO(4). Carmine molecules were concentrated in the polymer-rich phase, indicating an enthalpic specific interaction between carmine and the pseudopolycation, which is formed by cation adsorption along the macromolecule chain. When the enthalpic carmine-pseudopolycation interaction decreases, entropic forces dominate the natural dye-transfer process, and the carmine partitioning coefficient decreases. The optimization of the extraction process was obtained by a central composite face-centered (CCF) design. The CCF design was used to evaluate the influence of Li(2)SO(4) and PEO 1500 concentration and of the pH on the partition coefficient of carmine. The conditions that maximize the partition of carmine into the top phase were determined to be high concentrations of PEO and Li(2)SO(4) and low pH values within the ranges studied. PMID:19800067

  18. Can affinity interactions influence the partitioning of glucose-6-phosphate dehydrogenase in two-phase aqueous micellar systems?

    Directory of Open Access Journals (Sweden)

    André M. Lopes

    2008-01-01

    Full Text Available In this work, we provide an investigation of the role and strength of affinity interactions on the partitioning of the glucose-6-phosphate dehydrogenase in aqueous two-phase micellar systems. These systems are constituted of micellar surfactant solutions and offer both hydrophobic and hydrophilic environments, providing selectivity to biomolecules. We studied G6PD partitioning in systems composed of the nonionic surfactants, separately, in the presence and absence of affinity ligands. We observed that G6PD partitions to the micelle-poor phase, owing to the strength of excluded-volume interactions in these systems that drive the protein to the micelle-poor phase, where there is more free volume available.

  19. Correlations for the partition behavior of proteins in aqueous two-phase systems

    DEFF Research Database (Denmark)

    Schmidt, A.S.; Andrews, B.A.; Asenjo, J.A.

    1996-01-01

    was lower than that of subtilisin which was probably due to its higher hydrophobicity and, hence, a stronger salting-out effect. The protein concentration in each of the two phases was correlated with a ''saturation''-type equation. The partition coefficient could be satisfactorily predicted, as a function...... of the overall protein concentration, by the ratio between the ''saturation'' equations of the two individual phases. Better correlations were obtained when an empirical sigmoidal Boltzmann equation was fitted to the data, since in virtually all cases the partition coefficient is constant at low protein...... with 3% w/w NaCl was used for alpha-amylase. The concentration of the protein in each of the phases affected its partition behavior. The pattern for the individual proteins was dependent on their physicochemical properties. In the top phase, maximum protein concentration was determined mainly by a steric...

  20. Design and development of single stage purification of papain using Ionic Liquid based aqueous two phase extraction system and its Partition coefficient studies

    OpenAIRE

    Senthilkumar Rathnasamy; R.Kumaresan2

    2013-01-01

    As an emerging trend in bioseparation, aqueous two phase extractions based on phosponium ionic liquid have been utilized in this work to extract papain from Carica papaya fruit latex and the same wascompared with conventional aqueous two phase extraction system. Factors affecting the partition coefficient of papain such as ionic liquid concentration, pH of the extraction system and temperature have been investigated. The optimization studies show that ionic liquid concentrations and pH are ma...

  1. Design of functional guanidinium ionic liquid aqueous two-phase systems for the efficient purification of protein

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Xueqin; Wang, Yuzhi, E-mail: wyzss@hnu.edu.cn; Zeng, Qun; Chen, Jing; Huang, Yanhua; Xu, Kaijia

    2014-03-01

    Graphical abstract: - Highlights: • A series of novel cationic functional hexaalkylguanidinium ionic liquids and anionic functional tetraalkylguanidinium ionic liquids have been synthesized. • Functional guanidinium ionic liquid aqueous two-phase systems have been first designed for the purification of protein. • Mechanisms and performances of the process were researched. • Simple, green, safety and presents better purified ability than ordinary process. • A potential efficient platform for protein purification and related studies. - Abstract: A series of novel cationic functional hexaalkylguanidinium ionic liquids and anionic functional tetraalkylguanidinium ionic liquids have been devised and synthesized based on 1,1,3,3-tetramethylguanidine. The structures of the ionic liquids (ILs) were confirmed by {sup 1}H nuclear magnetic resonance ({sup 1}H NMR) and 13C nuclear magnetic resonance (13C NMR) and the production yields were all above 90%. Functional guanidinium ionic liquid aqueous two-phase systems (FGIL-ATPSs) have been first designed with these functional guanidinium ILs and phosphate solution for the purification of protein. After phase separation, proteins had transferred into the IL-rich phase and the concentrations of proteins were determined by measuring the absorbance at 278 nm using an ultra violet visible (UV–vis) spectrophotometer. The advantages of FGIL-ATPSs were compared with ordinary ionic liquid aqueous two-phase systems (IL-ATPSs). The proposed FGIL-ATPS has been applied to purify lysozyme, trypsin, ovalbumin and bovine serum albumin. Single factor experiments were used to research the effects of the process, such as the amount of ionic liquid (IL), the concentration of salt solution, temperature and the amount of protein. The purification efficiency reaches to 97.05%. The secondary structure of protein during the experimental process was observed upon investigation using UV–vis spectrophotometer, Fourier-transform infrared

  2. Measurement and Correlation of Partition Coefficients of Baicalin in EOPO/Salt Aqueous Two-Phase Systems

    Institute of Scientific and Technical Information of China (English)

    李伟; 朱自强

    2002-01-01

    The partition coefficients of baicalin were measured in ethylene oxide and propylene oxide(EOPO)/salt aqueous two-phase systems at 298.15K,It was found that most of baicalin partitioned into EOPO-rich phase.The partition coefficients of baicalin varied from 10 to 120.The effect of various factors,including tie-line lngth,salt composition,molecular weight of EOPO,and solution pH,on the partition behavior was investigated on EOPO/salt systems.Furthermore the partition coefficients of baicalin were correlated using the modified Diamond-Hsu model.Good agreement with experimental data is obtained.The average relative deviations are less than 5.0%.

  3. Phase Diagrams of the Aqueous Two-Phase Systems of Poly(ethylene glycol/Sodium Polyacrylate/Salts

    Directory of Open Access Journals (Sweden)

    Adalberto Pessoa Junior

    2011-03-01

    Full Text Available Aqueous two-phase systems consisting of polyethylene glycol (PEG, sodium polyacrylate (NaPAA, and a salt have been studied. The effects of the polymer size, salt type (NaCl, Na2SO4, sodium adipate and sodium azelate and salt concentrations on the position of the binodal curve were investigated. The investigated PEG molecules had a molar mass of 2,000 to 8,000 g/mol, while that of NaPAA was 8,000 g/mol. Experimental phase diagrams, and tie lines and calculated phase diagrams, based on Flory-Huggins theory of polymer solutions are presented. Due to strong enthalpic and entropic balancing forces, the hydrophobicity of the added salt has a strong influence on the position of the binodal, which could be reproduced by model calculations.

  4. Cell separation in immunoaffinity partition in aqueous polymer two-phase systems

    Science.gov (United States)

    Karr, Laurel J.; Van Alstine, James M.; Snyder, Robert S.; Shafer, Steven G.; Harris, J. Milton

    1989-01-01

    Two methods for immunoaffinity partitioning are described. One technique involves the covalent coupling of poly (ethylene glycol) (PEG) to immunoglobulin G antibody preparations. In the second method PEG-modified Protein A is used to complex with cells and unmodified antibody. The effects of PEG molecular weight, the degree of modification, and varying phase system composition on antibody activity and its affinity for the upper phase are studied. It is observed that both methods resulted in effective cell separation.

  5. Formation and characteristics of aqueous two-phase systems formed by a cationic surfactant and a series of ionic liquids.

    Science.gov (United States)

    Wei, Xi-Lian; Wang, Xiu-Hong; Ping, A-Li; Du, Pan-Pan; Sun, De-Zhi; Zhang, Qing-Fu; Liu, Jie

    2013-11-15

    Aqueous two-phase systems (ATPS) were obtained in the aqueous mixtures of a cationic surfactant and a series of ionic liquids (ILs). The effects of IL structure, temperature and additives on the phase separation were systematically investigated. The microstructures of some ATPS were observed by freeze-fracture replication technique. Lyotropic liquid crystal was found in the bottom phase besides micelles under different conditions. Remarkably, both IL structure and additives profoundly affected the formation and properties of the ATPSs. The phase separation can be attributed to the existence of different aggregates and the cation-π interactions of the cationic surfactant with the ILs, which has a significant role in the formation of ATPS. The extraction capacity of the studied ATPS was also evaluated through their application in the extraction of two biosubstances. The results indicate that the ILs with BF4(-) as anion show much better extraction efficiencies than the corresponding ILs with Br(-) as anion do under the same conditions. l-Tryptophan was mainly distributed into the NPTAB-rich phase, while methylene blue and capsochrome were mainly in the IL-rich phase.

  6. Extraction and purification of anthraquinones derivatives from Aloe vera L. using alcohol/salt aqueous two-phase system.

    Science.gov (United States)

    Tan, Zhi-jian; Li, Fen-fang; Xu, Xue-lei

    2013-08-01

    An alcohol/salt aqueous two-phase system (ATPS) composed of 1-propanol and (NH4)2SO4 was employed to purify anthraquinones (AQs) extracted from Aloe vera L. The main influencing system parameters such as type of alcohol, type and concentration of salt, temperature and pH were investigated in detail. Under the optimal extraction conditions, AQs can be extracted into alcohol-rich phase with high extraction efficiency, meanwhile majority polysaccharides, proteins, mineral substances and other impurities were extracted into salt-rich phase. Partitioning of AQs is dependent on hydrophobic interaction, hydrogen bond interaction, and salting-out effect in ATPS. Temperature also played a great role in the partitioning. After ATPS extraction, alcohol can be recycled by evaporation; moreover, salt can be recycled by dilution crystallization method. Compared with other liquid-liquid extractions, this alcohol/salt system is much simpler, lower in cost with easier recovery of phase-forming components, which has the potential scale-up in down-processing of active ingredients in plant.

  7. Partitioning of L-methionine in aqueous two-phase systems containing poly(propylene glycol) and sodium phosphate salts

    Energy Technology Data Exchange (ETDEWEB)

    Salabat, Alireza, E-mail: a-salabat@araku.ac.ir [Chemistry Department, Arak University, P.O. Box 38156-879, Arak (Iran, Islamic Republic of); Sadeghi, Rahmat [Department of Chemistry, University of Kurdistan, Sanandaj, Kurdistan 66135 (Iran, Islamic Republic of); Moghadam, Somayeh Tiani [Chemistry Department, Arak University, P.O. Box 38156-879, Arak (Iran, Islamic Republic of); Jamehbozorg, Bahman [Department of Chemistry, University of Kurdistan, Sanandaj, Kurdistan 66135 (Iran, Islamic Republic of)

    2011-10-15

    Highlights: > Thermodynamics parameters for partitioning of L-methionine in ATPS. > Investigation of different effects on partition coefficient of the amino acid. > Propose the best condition for L-methionine partitioning. - Abstract: The partitioning behavior of L-methionine has been studied in aqueous two-phase systems of (poly(propylene glycol) + sodium phosphate salts + H{sub 2}O) at different temperatures. The salts used were sodium di-hydrogen phosphate (NaH{sub 2}PO{sub 4}), di-sodium hydrogen phosphate (Na{sub 2}HPO{sub 4}) and tri-sodium phosphate (Na{sub 3}PO{sub 4}). The effects of tie line length, salt type, and temperature on the partition coefficient of this amino acid have been studied. In addition, thermodynamic parameters ({Delta}H{sup o}, {Delta}S{sup o} and {Delta}G{sup o}) as a function of temperature were calculated. The results showed that increasing tie line length led to decreasing of the partition coefficient. We also showed that the partition coefficients of the amino acid in the systems containing Na{sub 3}PO{sub 4} are greater than the other two salts. Moreover, it is verified that increasing temperature led to decreasing the partition coefficient. The experimental partition coefficient data are correlated using a modified virial-type model.

  8. Purification of C-phycocyanin from Spirulina platensis in aqueous two-phase systems using an experimental design

    Directory of Open Access Journals (Sweden)

    Francine Silva Antelo

    2015-02-01

    Full Text Available C-phycocyanin from Spirulina platensis was purified in aqueous two-phase systems (ATPS of polyethylene glycol (PEG/potassium phosphate, varying the molar mass of the PEG. Results using a full factorial design showed that an increase in the concentration of salt and decrease in the concentration of PEG caused an increment in the purification factor for all the ATPS studied. Optimization of the conditions of the purification was studied using a central composite rotatable design for each molar mass of PEG. The ATPS composed of 7% (w/w PEG 1500 or 4% (w/w PEG 8000 (g/gmol and 23 or 22.5% (w/w of phosphate resulted a purification factor of 1.6-fold for C-phycocyanin, with total and 57% recovery, respectively. Process conditions were optimized for the purification factor for the system with PEG 1500. The ATPS with 4% (w/w PEG 4000 or 4% (w/w PEG 6000 and 21% (w/w phosphate resulted purification factors of 2.1 and 2.2-fold, recovering 100% and 73.5%, respectively of C-phycocyanin in the top phase.

  9. Recovery of laccase from processed Hericium erinaceus (Bull.:Fr) Pers. fruiting bodies in aqueous two-phase system.

    Science.gov (United States)

    Rajagopalu, Devamalini; Show, Pau Loke; Tan, Yee Shin; Muniandy, Sekaran; Sabaratnam, Vikineswary; Ling, Tau Chuan

    2016-09-01

    The feasible use of aqueous two-phase systems (ATPSs) to establish a viable protocol for the recovery of laccase from processed Hericium erinaceus (Bull.:Fr.) Pers. fruiting bodies was evaluated. Cold-stored (4.00±1.00°C) H. erinaceus recorded the highest laccase activities of 2.02±0.04 U/mL among all the processed techniques. The evaluation was carried out in twenty-five ATPSs, which composed of polyethylene glycol (PEG) with various molecular weights and potassium phosphate salt solution to purify the protein from H. erinaceus. Optimum recovery condition was observed in the ATPS which contained 17% (w/w) PEG with a molecular weight of 8000 and 12.2% (w/w) potassium phosphate solution, at a volume ratio (VR) of 1.0. The use of ATPS resulted in one-single primary recovery stage process that produced an overall yield of 99% with a purification factor of 8.03±0.46. The molecular mass of laccases purified from the bottom phase was in the range of 55-66 kDa. The purity of the partitioned laccase was confirmed with sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). PMID:26922478

  10. Development of green betaine-based deep eutectic solvent aqueous two-phase system for the extraction of protein.

    Science.gov (United States)

    Li, Na; Wang, Yuzhi; Xu, Kaijia; Huang, Yanhua; Wen, Qian; Ding, Xueqin

    2016-05-15

    Six kinds of new type of green betaine-based deep eutectic solvents (DESs) have been synthesized. Deep eutectic solvent aqueous two-phase systems (DES-ATPS) were established and successfully applied in the extraction of protein. Betaine-urea (Be-U) was selected as the suitable extractant. Single factor experiments were carried out to determine the optimum conditions of the extraction process, such as the salt concentration, the mass of DES, the separation time, the amount of protein, the temperature and the pH value. The extraction efficiency could achieve to 99.82% under the optimum conditions. Mixed sample and practical sample analysis were discussed. The back extraction experiment was implemented and the back extraction efficiency could reach to 32.66%. The precision experiment, repeatability experiment and stability experiment were investigated. UV-vis, FT-IR and circular dichroism (CD) spectra confirmed that the conformation of protein was not changed during the process of extraction. The mechanisms of extraction were researched by dynamic light scattering (DLS), the measurement of the conductivity and transmission electron microscopy (TEM). DES-protein aggregates and embraces phenomenon play considerable roles in the separation process. All of these results indicated that betaine-based DES-ATPS may provide a potential substitute new method for the separation of proteins. PMID:26992491

  11. Relative hydrophobicity between the phases and partition of cytochrome-c in glycine ionic liquids aqueous two-phase systems.

    Science.gov (United States)

    Wu, Changzeng; Wang, Jianji; Li, Zhiyong; Jing, Jun; Wang, Huiyong

    2013-08-30

    In this work, glycine ionic liquids tetramethylammonium glycine ([N1111][Gly]), tetraethylammonium glycine ([N2222][Gly]), tetra-n-butylammonium glycine ([N4444][Gly]), tetra-n-butylphosphonium glycine ([P4444][Gly]) and tetra-n-pentylammonium glycine ([N5555][Gly]) were synthesized and used to prepare aqueous two-phase systems (ATPSs) in the presence of K2HPO4. Binodal curves of such ATPSs and partition coefficients of a series of dinitrophenylated (DNP) amino acids in these ATPSs were determined at 298.15K to understand the effect of cationic structure of the ionic liquids on the phase-forming ability of glycine ionic liquids, relative hydrophobicity between the phases in the ionic liquids ATPSs, and polarity of the ionic liquids-rich phases. With the attempt to correlate the relative hydrophobicity of the phases in the ATPSs with their extraction capability for proteins, partition coefficients of cytochrome-c in the ATPSs were also determined. It was shown that partition coefficients of cytochrome-c were in the range from 2.83 to 20.7 under the studied pH conditions. Then, hydrophobic interactions between cytochrome-c and the ionic liquid are suggested to be the main driving force for the preferential partition of cytochrome-c in the glycine ionic liquid-rich phases of the ATPSs. Result derived from polarity of the ionic liquids-rich phases supports this mechanism.

  12. Salt effect on the (polyethylene glycol 8000 + sodium sulfate) aqueous two-phase system: Relative hydrophobicity of the equilibrium phases

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, Luisa A., E-mail: laferreira@deb.uminho.pt [IBB - Institute for Biotechnology and Bioengineering, Centre for Biological Engineering, Universidade do Minho, Campus de Gualtar, 4710-057 Braga (Portugal); Teixeira, Jose A. [IBB - Institute for Biotechnology and Bioengineering, Centre for Biological Engineering, Universidade do Minho, Campus de Gualtar, 4710-057 Braga (Portugal)

    2011-08-15

    Highlights: > Gibbs free energy of transfer of a methylene group on PEG 8000 - Na{sub 2}SO{sub 4} ATPS. > Influence of salt additive on the hydrophobic character of the coexisting phases. > Partitioning behavior of a series of five sodium salts of DNP-amino acids. > A relationship between {Delta}G(CH{sub 2}), TLL and I of the salt additive was established. - Abstract: The relative hydrophobicity of the phases of several {l_brace}polyethylene glycol (PEG) 8000 + sodium sulfate (Na{sub 2}SO{sub 4}){r_brace} aqueous two-phase systems (ATPSs), all containing 0.01 mol . L{sup -1} sodium phosphate buffer (NaPB, pH 7.4) and increasing concentration of a salt additive, NaCl or KCl, up to 1.0 mol . L{sup -1}, was measured by the free energy of transfer of a methylene group between the phases, {Delta}G(CH{sub 2}). The {Delta}G(CH{sub 2}) of the systems was determined by partitioning of a homologous series of five sodium salts of dinitrophenylated (DNP) - amino acids with aliphatic side chains in three different tie-lines of each biphasic system. The relative hydrophobicity of the phases ranged from -0.125 to -0.183 kcal . mol{sup -1}, being the NaCl salt the one to provide the more effective changes. The results show that, within each system, there is a linear relationship between the {Delta}G(CH{sub 2}) and the tie-line length (TLL), and biphasic systems with high salt additive concentration present the most negative {Delta}G(CH{sub 2}) values. Therefore, the feasibility of establishing a relationship between the relative hydrophobicity of the phases in a given TLL and the ionic strength of the salt additive was investigated and a satisfactory correlation was found for each salt.

  13. Extraction of natural red colorants from the fermented broth of Penicillium purpurogenum using aqueous two-phase polymer systems.

    Science.gov (United States)

    Santos-Ebinuma, Valéria Carvalho; Lopes, André Moreni; Pessoa, Adalberto; Teixeira, Maria Francisca Simas

    2015-01-01

    Safety concerns related to the increasing and widespread application of synthetic coloring agents have increased the demand for natural colorants. Fungi have been employed in the production of novel and safer colorants. In order to obtain the colorants from fermented broth, suitable extraction systems must be developed. Aqueous two-phase polymer systems (ATPPS) offer a favorable chemical environment and provide a promising alternative for extracting and solubilizing these molecules. The aim of this study was to investigate the partitioning of red colorants from the fermented broth of Penicillium purpurogenum using an ATPPS composed of poly(ethylene glycol) (PEG) and sodium polyacrylate (NaPA). Red colorants partitioned preferentially to the top (PEG-rich phase). In systems composed of PEG 6,000 g/mol/NaPA 8,000 g/mol, optimum colorant partition coefficient (KC ) was obtained in the presence of NaCl 0.1 M (KC  = 10.30) while the PEG 10,000 g/mol/NaPA 8,000 g/mol system in the presence of Na2 SO4 0.5 M showed the highest KC (14.78). For both polymers, the mass balance (%MB) and yield in the PEG phase (%ηTOP ) were close to 100 and 79%, respectively. The protein selectivity in all conditions evaluated ranged from 2.0-3.0, which shows a suitable separation of the red colorants and proteins present in the fermented broth. The results suggest that the partitioning of the red colorants is dependent on both the PEG molecular size and salt type. Furthermore, the results obtained support the potential application of ATPPS as the first step of a purification process to recover colorants from fermented broth of microorganisms. PMID:26097197

  14. Microcalorimetric Study on the Oscillating System of Two-phase Reaction of Aqueous Acid with Primary Amine in Chloroform

    Institute of Scientific and Technical Information of China (English)

    ZHANG,Hong-Lin; YU,Xiu-Fang; LU,Cheng-Xue; SUN,Si-Xiu; GUO,Guo-Hua; FU,Xun

    2003-01-01

    It has been found that the two-phase reactions of aqueous HCl,HOAc or H3PO4 with primary amine N1923 in chloroform are oscillating reactions. Their power-time curves were measured by the titration microcalorimetric method, and the induction period (tin).The first oscillating period (tp.1) and the second oscillating period(tp.2 ) were determined.The apparent activating parameters and the orders of the oscillating systems were calculated and the following relationships were established: for the oscillating system of hydrochloric acid tin∝c0.147HCIexp(1.35×103/T),.tp.1∝c0.241HCI·exp(4.33×103/T),tp.2∝c0.290HCIexp(5.59×103/T);for the oscillating system of acetic acid, tm∝c0.883HOAcexp(2.32×103/T),tp.1∝c0.399HOAc·exp(4.50×103/T),tp.2∝c0.301HOAcexp(5.88×103/T),for the oscillating system of phosphoric acid, tim∝c1.14H3PO4exp(7.70×104]T),tp.1∝c1.42H3PO4exp(1.14×104/T),tp.2∝c1.47H3PO4exp(1.27×104/T).

  15. Partitioning and purification of extracellular β-1,3-1,4-glucanase in aqueous two-phase systems

    Institute of Scientific and Technical Information of China (English)

    HE Guo-qing; ZHANG Xiu-yan; TANG Xing-jun; CHEN Qi-he; RUAN Hui

    2005-01-01

    The partition behaviors of β-1,3-1,4-glucanase, α-amylase and neutral proteases from clarified and whole fermentation broths of Bacillus subtilis ZJF-1A5 were investigated. An aqueous two-phase system (polyethylene glycol (PEG)/MgSO4)was examined with regard to the effects of PEG molecular weight (MW) and concentration, MgSO4 concentration, pH and NaCl concentration on enzyme partition and extraction. The MW and concentration of PEG were found to have significant effects on enzyme partition and extraction with low MW PEG showing the greatest benefit in the partition and extraction of β-glucanase with the PEG/MgSO4 system. MgSO4 concentration influenced the partition and extraction of β-glucanase significantly. pH had little effect on β-glucanase or proteases partition but affected α-amylase partition when pH was over 7.0. The addition of NaCl had little effect on the partition behavior of β-glucanase but had very significant effects on the partitioning of α-amylase and on the neutral proteases. The partition behaviors of β-glucanase, α-amylase and proteases in whole broth were also investigated and results were similar to those obtained with clarified fermentation broth. A two-step process for purifying β-glucanase was developed, which achieved β-glucanase recovery of 65.3% and specific activity of 14027 U/mg, 6.6 times improvement over the whole broth.

  16. Influence of salts on the coexistence curve and protein partitioning in nonionic aqueous two-phase micellar systems

    Directory of Open Access Journals (Sweden)

    A. M. Lopes

    2014-12-01

    Full Text Available Aqueous two-phase micellar systems (ATPMS can be exploited in separation science for the extraction/purification of desired biomolecules. Prior to phase separation the surfactant solution reaches a cloud point temperature, which is influenced by the presence of electrolytes. In this work, we provide an investigation on the cloud point behavior of the nonionic surfactant C10E4 in the presence of NaCl, Li2SO4 and KI. We also investigated the salts' influence on a model protein partitioning. NaCl and Li2SO4 promoted a depression of the cloud point. The order of salts and the concentration that decreased the cloud point was: Li2SO4 0.5 M > NaCl 0.5 M ≈ Li2SO4 0.2 M. On the other hand, 0.5 M KI dislocated the curve to higher cloud point values. For our model protein, glucose-6-phosphate dehydrogenase (G6PD, partitioning experiments with 0.5 M NaCl or 0.2 M Li2SO4 at 13.85 ºC showed similar results, with K G6PD ~ 0.46. The lowest partition coefficient was obtained in the presence of 0.5 M KI (K G6PD = 0.12, with major recovery of the enzyme in the micelle-dilute phase (%Recovery = 90%. Our results show that choosing the correct salt to add to ATPMS may be useful to attain the desired partitioning conditions at more extreme temperatures. Furthermore, this system can be effective to separate a target biomolecule from fermented broth contaminants.

  17. Partition separation and characterization of the polyhydroxyalkanoates synthase produced from recombinant Escherichia coli using an aqueous two-phase system.

    Science.gov (United States)

    Lan, John Chi-Wei; Yeh, Chun-Yi; Wang, Chih-Chi; Yang, Yu-Hsuan; Wu, Ho-Shing

    2013-10-01

    Polyhydroxyalkanoates (PHAs) are renewable and biodegradable polyesters which can be synthesized either by numerous of microorganisms in vivo or synthase in vitro. The synthesis of PHAs in vitro requires an efficient separation for high yield of purified enzyme. The recombinant Escherichia coli harboring phaC gene derived from Ralstonia eutropha H16 was cultivated in the chemically defined medium for overexpression of synthase in the present work. The purification and characteristics of PHA synthase from clarified feedstock by using aqueous two-phase systems (ATPS) was investigated. The optimized concentration of ATPS for partitioning PHA synthase contained polyethylene glycol 6000 (30%, w/w) and potassium phosphate (8%, w/w) with 3.25 volume ratio in the absence of NaCl at pH 8.7 and 4°C. The results showed that the partition coefficient of enzyme activity and protein content are 6.07 and 0.22, respectively. The specific activity, selectivity, purification fold and recovery of phaC(Re) achieved 1.76 U mg⁻¹, 29.05, 16.23 and 95.32%, respectively. Several metal ions demonstrated a significant effect on activity of purified enzyme. The purified enzyme displayed maximum relative activity as operating condition at pH value of 7.5 and 37°C. As compared to conventional purification processes, ATPS can be a promising technique applied for rapid recovery of PHA synthase and preparation of large quantity of PHA synthase on synthesis of P(3HB) in vitro.

  18. Extraction of penicillin G by aqueous two-phase system of [Bmim]BF4/NaH2PO4

    Institute of Scientific and Technical Information of China (English)

    LIU Qingfen; HU Xuesheng; WANG Yuhong; YANG Ping; XIA Hansong; YU Jiang; LIU Huizhou

    2005-01-01

    A novel approach for the extraction of penicillin G by aqueous two-phase system comprised of hydrophilic ionic liquid [Bmim]BF4 (1-butyl-3- methylimidazolium tetrafluoroborate) and NaH2PO4 is reported. The effects of some important parameters involving the concentration of NaH2PO4, the concentration of penicillin G, the amount of [Bmim]BF4 on the formation of aqueous two-phase system and the extraction yield of penicillin were investigated. The primary result shows that the ATPS can take advantage of penicillin concentrated in upper phase at higher pH value for penicillin extraction from its aqueous solution without emulsification.

  19. Purification of a fibrinolytic protease from Mucor subtilissimus UCP 1262 by aqueous two-phase systems (PEG/sulfate).

    Science.gov (United States)

    Nascimento, Thiago Pajeú; Sales, Amanda Emmanuelle; Porto, Camila Souza; Brandão, Romero Marcos Pedrosa; de Campos-Takaki, Galba Maria; Teixeira, José Antônio Couto; Porto, Tatiana Souza; Porto, Ana Lúcia Figueiredo; Converti, Attilio

    2016-07-01

    A fibrinolytic protease from M. subtilissimus UCP 1262 was recovered and partially purified by polyethylene glycol (PEG)/sodium sulfate aqueous two-phase systems (ATPS). The simultaneous influence of PEG molar mass, PEG concentration and sulfate concentration on the enzyme recovery was first investigated using a 2(3) full factorial design, and the Response Surface Methodology used to identify the optimum conditions for enzyme extraction by ATPS. Once the best PEG molar mass for the process had been selected (6000g/mol), a two-factor central composite rotary design was applied to better evaluate the effects of the other two independent variables. The fibrinolytic enzyme was shown to preferentially partition to the bottom phase with a partition coefficient (K) ranging from 0.2 to 0.7. The best results in terms of enzyme purification were obtained with the system formed by 30.0% (w/w) PEG 6000g/mol and 13.2% (w/w) sodium sulfate, which ensured a purification factor of 10.0, K of 0.2 and activity yield of 102.0%. SDS-PAGE and fibrin zymography showed that the purified protease has a molecular mass of 97kDa and an apparent isoelectric point of 5.4. When submitted to assays with different substrates and inhibitors, it showed selectivity for succinyl-l-ala-ala-pro-l-phenylalanine-p-nitroanilide and was almost completely inhibited by phenylmethylsulfonyl fluoride, behaving as a chymotrypsin-like protease. At the optimum temperature of 37°C, the enzyme residual activity was 94 and 68% of the initial one after 120 and 150min of incubation, respectively. This study demonstrated that M. subtilissimus protease has potent fibrinolytic activity compared with similar enzymes produced by solid-state fermentation, therefore it may be used as an agent for the prevention and therapy of thrombosis. Furthermore, it appears to have the advantages of low cost production and simple purification. PMID:27183214

  20. Transformation of Vesicles in Aqueous Two-Phase System of an Anionic Gemini Surfactant and a Cationic Conventional Surfactant Mixture

    Institute of Scientific and Technical Information of China (English)

    JIANG Rong; HUANG Yi-Xiong; ZHAO Jian-Xi; HUANG Chang-Cang

    2008-01-01

    Transformation of vesicles formed in DTAB/C11-p-PhCNa aqueous surfactant two-phase (ASTP) was observed by the transmission electron microscopy (TEM). The trans-conformation of the gemini surfactant in the aggregates was considered to be the important factor for constructing the multi-lamellar structure of the vesicle wall. The cation-π interaction between the quaternary ammonium cation and the aromatic ring in the spacer was determined by the UV-Vis spectrum analysis, which, as well as the general electrostatic attraction and hydrophobic force, contributes to the stability of the multi-lamellar structure. The concentrations of the surface-active ions were measured for understanding the mechanism of vesicle transformation. The results show that isoelectric mixing of the two components benefits the growth of vesicles both in size and wall thickness.

  1. Recovery of ascorbic oxidoreductase from crude extract with an aqueous two-phase system in a perforated rotating disc contactor

    Directory of Open Access Journals (Sweden)

    Ana Lúcia Figueiredo Porto

    2004-09-01

    Full Text Available A continuous perforated rotating disc contactor was used to extract the enzyme ascorbic oxidoreductase (E.C.1.10.3.3 from crude extract of Curcubita maxima with an aqueous two-phase system of poly (ethylene glycol and phosphate salts. The effect of dispersed phase velocity on either protein mass transfer coefficients or separation efficiency at 1, 2 and 3 mL/min was studied. An increase of the mass transfer coefficients was observed with the dispersed phase velocity, while the separation efficiency showed a small decrease with the increase of this parameter. The experimental results obtained during continuous extraction showed that the ascorbic oxidoreductase activity was partitioned preferentially into the salt-rich phase in all conditions studied. The best recovery of enzyme activity was 236%, with a purification factor of 34 in flow rates of 1 mL/min for dispersed phase.Uma coluna de discos perfurados rotativos foi utilizada na extração da enzima ascorbato oxidorredutase (E.C.1.10.3.3, obtida do extrato bruto de Curcubita maxima, através da utilização do sistema bifásico aquoso Polietilenoglicol-sais de fosfato. Os efeitos da velocidade da fase dispersa nos coeficientes de transferência de massa e na eficiência de separação para valores de 1, 2 e 3 mL/min foram estudados. Observou-se um aumento da transferência de massa com a velocidade da fase dispersa, enquanto que a eficiência de separação demonstrou uma ligeira redução com o aumento deste parâmetro. Os resultados experimentais obtidos durante a extração contínua demonstraram que a atividade da ascorbato oxidorredutase se concentrou preferencialmente na fase rica em sal para todas as condições estudadas. A maior recuperação da atividade enzimática foi de 236%, com um fator de purificação de 34 para o valor de 1 mL/min para a fase dispersa.

  2. Liquid-liquid equilibrium of water + PEG 8000 + magnesium sulfate or sodium sulfate aqueous two-phase systems at 35°C: experimental determination and thermodynamic modeling

    Directory of Open Access Journals (Sweden)

    B. D. Castro

    2005-09-01

    Full Text Available Liquid-liquid extraction using aqueous two-phase systems is a highly efficient technique for separation and purification of biomolecules due to the mild properties of both liquid phases. Reliable data on the phase behavior of these systems are essential for the design and operation of new separation processes; several authors reported phase diagrams for polymer-polymer systems, but data on polymer-salt systems are still relatively scarce. In this work, experimental liquid-liquid equilibrium data on water + polyethylene glycol 8000 + magnesium sulfate and water + polyethylene glycol 8000 + sodium sulfate aqueous two-phase systems were obtained at 35°C. Both equilibrium phases were analyzed by lyophilization and ashing. Experimental results were correlated with a mass-fraction-based NRTL activity coefficient model. New interaction parameters were estimated with the Simplex method. The mean deviations between the experimental and calculated compositions in both equilibrium phases is about 2%.

  3. Study of the applicability of non-conventional aqueous two-phase systems in counter-current and centrifugal partition chromatography.

    Science.gov (United States)

    Bezold, Franziska; Goll, Johannes; Minceva, Mirjana

    2015-04-01

    Aqueous two-phase systems composed of imidazolium-based ionic liquids and phosphate salts were evaluated for their applicability in liquid-liquid chromatography. The influence of the nature of ionic liquid anion and cation on the partitioning of bovine serum albumin, lysozyme and myoglobin was investigated. A mixture of K2HPO4 and KH2PO4 in a ratio of 1.82:1 wt/wt was used in all of the tested biphasic systems to adjust the pH to a range of 7-8. The results show that more hydrophobic cations decrease the partition coefficients of the proteins in the biphasic systems and outweigh the effect of the anion on the distribution of the macromolecules. Viscosities and densities of the biphasic systems were in a suitable range for liquid-liquid chromatography. Even though the partition coefficients were too high for a conventional batch operation mode, these aqueous two-phase systems show favorable properties for protein capturing in liquid-liquid chromatographic columns. Additionally, the possible application of ionic liquids as modifiers in polyethylene glycol (PEG)-based aqueous two-phase systems was investigated. It could be demonstrated that ionic liquids alter the partition coefficients of the proteins. PMID:25736304

  4. A Novel Aqueous Two Phase System Composed of Surfactant and Xylitol for the Purification of Lipase from Pumpkin (Cucurbita moschata Seeds and Recycling of Phase Components

    Directory of Open Access Journals (Sweden)

    Mehrnoush Amid

    2015-06-01

    Full Text Available Lipase is one of the more important enzymes used in various industries such as the food, detergent, pharmaceutical, textile, and pulp and paper sectors. A novel aqueous two-phase system composed of surfactant and xylitol was employed for the first time to purify lipase from Cucurbita moschata. The influence of different parameters such as type and concentration of surfactants, and the composition of the surfactant/xylitol mixtures on the partitioning behavior and recovery of lipase was investigated. Moreover, the effect of system pH and crude load on the degree of purification and yield of the purified lipase were studied. The results indicated that the lipase was partitioned into the top surfactant rich phase while the impurities partitioned into the bottom xylitol-rich phase using an aqueous two phase system composed of 24% (w/w Triton X-100 and 20% (w/w xylitol, at 56.2% of tie line length (TLL, (TTL is one of the important parameters in this study and it is determined from a bimodal curve in which the tie-line connects two nodes on the bimodal, that represent concentration of phase components in the top and bottom phases and a crude load of 25% (w/w at pH 8.0. Recovery and recycling of components was also measured in each successive step process. The enzyme was successfully recovered by the proposed method with a high purification factor of 16.4 and yield of 97.4% while over 97% of the phase components were also recovered and recycled. This study demonstrated that the proposed novel aqueous two phase system method is more efficient and economical than the traditional aqueous two phase system method for the purification and recovery of the valuable enzyme lipase.

  5. A Novel Aqueous Two Phase System Composed of Surfactant and Xylitol for the Purification of Lipase from Pumpkin (Cucurbita moschata) Seeds and Recycling of Phase Components.

    Science.gov (United States)

    Amid, Mehrnoush; Manap, Mohd Yazid; Hussin, Muhaini; Mustafa, Shuhaimi

    2015-06-17

    Lipase is one of the more important enzymes used in various industries such as the food, detergent, pharmaceutical, textile, and pulp and paper sectors. A novel aqueous two-phase system composed of surfactant and xylitol was employed for the first time to purify lipase from Cucurbita moschata. The influence of different parameters such as type and concentration of surfactants, and the composition of the surfactant/xylitol mixtures on the partitioning behavior and recovery of lipase was investigated. Moreover, the effect of system pH and crude load on the degree of purification and yield of the purified lipase were studied. The results indicated that the lipase was partitioned into the top surfactant rich phase while the impurities partitioned into the bottom xylitol-rich phase using an aqueous two phase system composed of 24% (w/w) Triton X-100 and 20% (w/w) xylitol, at 56.2% of tie line length (TLL), (TTL is one of the important parameters in this study and it is determined from a bimodal curve in which the tie-line connects two nodes on the bimodal, that represent concentration of phase components in the top and bottom phases) and a crude load of 25% (w/w) at pH 8.0. Recovery and recycling of components was also measured in each successive step process. The enzyme was successfully recovered by the proposed method with a high purification factor of 16.4 and yield of 97.4% while over 97% of the phase components were also recovered and recycled. This study demonstrated that the proposed novel aqueous two phase system method is more efficient and economical than the traditional aqueous two phase system method for the purification and recovery of the valuable enzyme lipase.

  6. A Novel Aqueous Two Phase System Composed of Surfactant and Xylitol for the Purification of Lipase from Pumpkin (Cucurbita moschata) Seeds and Recycling of Phase Components.

    Science.gov (United States)

    Amid, Mehrnoush; Manap, Mohd Yazid; Hussin, Muhaini; Mustafa, Shuhaimi

    2015-01-01

    Lipase is one of the more important enzymes used in various industries such as the food, detergent, pharmaceutical, textile, and pulp and paper sectors. A novel aqueous two-phase system composed of surfactant and xylitol was employed for the first time to purify lipase from Cucurbita moschata. The influence of different parameters such as type and concentration of surfactants, and the composition of the surfactant/xylitol mixtures on the partitioning behavior and recovery of lipase was investigated. Moreover, the effect of system pH and crude load on the degree of purification and yield of the purified lipase were studied. The results indicated that the lipase was partitioned into the top surfactant rich phase while the impurities partitioned into the bottom xylitol-rich phase using an aqueous two phase system composed of 24% (w/w) Triton X-100 and 20% (w/w) xylitol, at 56.2% of tie line length (TLL), (TTL is one of the important parameters in this study and it is determined from a bimodal curve in which the tie-line connects two nodes on the bimodal, that represent concentration of phase components in the top and bottom phases) and a crude load of 25% (w/w) at pH 8.0. Recovery and recycling of components was also measured in each successive step process. The enzyme was successfully recovered by the proposed method with a high purification factor of 16.4 and yield of 97.4% while over 97% of the phase components were also recovered and recycled. This study demonstrated that the proposed novel aqueous two phase system method is more efficient and economical than the traditional aqueous two phase system method for the purification and recovery of the valuable enzyme lipase. PMID:26091076

  7. Design and development of single stage purification of papain using Ionic Liquid based aqueous two phase extraction system and its Partition coefficient studies

    Directory of Open Access Journals (Sweden)

    Senthilkumar Rathnasamy

    2013-04-01

    Full Text Available As an emerging trend in bioseparation, aqueous two phase extractions based on phosponium ionic liquid have been utilized in this work to extract papain from Carica papaya fruit latex and the same wascompared with conventional aqueous two phase extraction system. Factors affecting the partition coefficient of papain such as ionic liquid concentration, pH of the extraction system and temperature have been investigated. The optimization studies show that ionic liquid concentrations and pH are majorly influencing the phaseformations and papain partitioning. It reveals the importance of electrostatic and hydrophobic interactions in the papain partitioning. Purification studies performed on Gel Filtration Chromatography shows that 96% of the papain enzyme could be extracted with the phosponium based ionic liquid in a single stage extraction. The final fraction containing papain enzyme was confirmed by SDS Page analysis.

  8. Simultaneous separation/enrichment and detection of trace ciprofloxacin and lomefloxacin in food samples using thermosensitive smart polymers aqueous two-phase flotation system combined with HPLC.

    Science.gov (United States)

    Lu, Yang; Chen, Bo; Yu, Miao; Han, Juan; Wang, Yun; Tan, Zhenjiang; Yan, Yongsheng

    2016-11-01

    Smart polymer aqueous two phase flotation system (SPATPF) is a new separation and enrichment technology that integrated the advantages of the three technologies, i.e., aqueous two phase system, smart polymer and flotation sublation. Ethylene oxide and propylene oxide copolymer (EOPO)-(NH4)2SO4 SPATPF is a pretreatment technique, and it is coupled with high-performance liquid chromatography to analyze the trace ciprofloxacin and lomefloxacin in real food samples. The optimized conditions of experiment were determined in the multi-factor experiment by using response surface methodology. The flotation efficiency of lomefloxacin and ciprofloxacin was 94.50% and 98.23% under the optimized conditions. The recycling experimentsshowed that the smart polymer EOPO could use repeatedly, which will reduce the cost in the future application. PMID:27211613

  9. pH recycling aqueous two-phase systems applied in extraction of Maitake β-Glucan and mechanism analysis using low-field nuclear magnetic resonance.

    Science.gov (United States)

    Hou, Huiyun; Cao, Xuejun

    2015-07-31

    In this paper, a recycling aqueous two-phase systems (ATPS) based on two pH-response copolymers PADB and PMDM were used in purification of β-Glucan from Grifola frondosa. The main parameters, such as polymer concentration, type and concentration of salt, extraction temperature and pH, were investigated to optimize partition conditions. The results demonstrated that β-Glucan was extracted into PADB-rich phase, while impurities were extracted into PMDM-rich phase. In this 2.5% PADB/2.5% PMDM ATPS, 7.489 partition coefficient and 96.92% extraction recovery for β-Glucan were obtained in the presence of 30mmol/L KBr, at pH 8.20, 30°C. The phase-forming copolymers could be recycled by adjusting pH, with recoveries of over 96.0%. Furthermore, the partition mechanism of Maitake β-Glucan in PADB/PMDM aqueous two-phase systems was studied. Fourier transform infrared spectra, ForteBio Octet system and low-field nuclear magnetic resonance (LF-NMR) were introduced for elucidating the partition mechanism of β-Glucan. Especially, LF-NMR was firstly used in the mechanism analysis in partition of aqueous two-phase systems. The change of transverse relaxation time (T2) in ATPS could reflect the interaction between polymers and β-Glucan.

  10. Production of dry Lactobacillus rhamnosus GG preparations by spray drying and lyophilization in aqueous two-phase systems

    Directory of Open Access Journals (Sweden)

    Katarzyna Leja

    2009-12-01

    Full Text Available Background. Drying is the oldest method of food preservation. It works by removing water from the food, which prevents the growth of microorganisms and decay. Moreover, spray or freeze drying is also used for the preservation of probiotic cultures. The aim of this study was to compare a survival rate of probiotic bacteria Lactobacillus rhamnosus during spray and freeze drying in ATPS. These results were also compared with survival rate of cells dried under the same conditions but suspended only in skim milk, 6% solution of PVP or 6% solution of dextran. Material and methods. The bacteria Lactobacillus rhamnosus GGwere suspended and spray or freeze dried in various types of aqueous two-phase emulsions: PVP/dextran, PEG4000/dextran and PEG8000/dextran. These emulsions consisted of different types of polymers and had varying ratio of polymers in dispersed (dextran and dispersing (PEG and PVP phases. Results. The research demonstrated that survival rate of bacteria directly after drying depended mainly on protective reagent, rather than on drying method. After 30-day-storage of the dried bacteria cell specimens, the highest survival rate was noted in case of freeze dried cells in milk. In case of spray drying the highest cell survival rate was observed when emulsion PVP3.6%/dextran2.4% was used as a drying medium. Conclusions. Finally, it has been found that cell survival rate was not strongly influenced by the storage temperature of the powder but it depended on the drying medium.  

  11. Countercurrent Chromatographic Separation of Lipophilic Ascorbic Acid Derivatives and Extract from Kadsura Coccinea Using Hydrophobic Organic-Aqueous Two-Phase Solvent Systems

    OpenAIRE

    Shinomiya, Kazufusa; Li, Heran; Kitanaka, Susumu; Ito, Yoichiro

    2009-01-01

    Countercurrent chromatographic (CCC) separation of lipophilic ascorbic acid derivatives and the crude extract from Kadsura Coccinea was performed using the type-J multilayer coil planet centrifuge with a hydrophobic organic-aqueous two-phase solvent system composed of n-hexane/ethyl acetate/ethanol/aqueous 0.1% trifluoroacetic acid at the volume ratio of (5 : 5 : 6 : 2). The lipophilic ascorbic acid derivatives were separated in the order of L-ascrobyl 2,6-dibutyrate, L-ascorbyl 6-palmitate a...

  12. Cell separation by immunoaffinity partitioning with polyethylene glycol-modified Protein A in aqueous polymer two-phase systems

    Science.gov (United States)

    Karr, Laurel J.; Van Alstine, James M.; Snyder, Robert S.; Shafer, Steven G.; Harris, J. Milton

    1988-01-01

    Previous work has shown that polyethylene glycol (PEG)-bound antibodies can be used as affinity ligands in PEG-dextran two-phase systems to provide selective partitioning of cells to the PEG-rich phase. In the present work it is shown that immunoaffinity partitioning can be simplified by use of PEG-modified Protein A which complexes with unmodified antibody and cells and shifts their partitioning into the PEG-rich phase, thus eliminating the need to prepare a PEG-modified antibody for each cell type. In addition, the paper provides a more rigorous test of the original technique with PEG-bound antibodies by showing that it is effective at shifting the partitioning of either cell type of a mixture of two cell populations.

  13. Polarity, selectivity and performance of hydrophilic organic/salt-containing aqueous two-phase system on counter-current chromatography for polar compounds.

    Science.gov (United States)

    Liu, Dan; Hong, Zhilai; Gao, Mingzhe; Wang, Zhixin; Gu, Ming; Zhang, Xiaozhe; Xiao, Hongbin

    2016-05-27

    The essential attributes of a solvent system for separation polar compounds on CCC are polarity, selectively and performance. Here, hydrophilic organic/salt-containing aqueous two-phase system (HO/S TPS) was evaluated as an alternative solvent system for CCC separation of polar compounds. Polarity measurements based on Rohrschneider-Snyder parameter was developed as quantitative assessing the polarity of HO/S TPS and comparing with an organic/aqueous system. All investigated 1-butanol/ethanol/saturated ammonium sulfate solution/water (BEAsWat) and 1-butanol/ethanol/saturated dipotassium hydrogen phosphate solution/water (BEDhpWat) systems with polarity values of organic phase from 4.5 to 6.8, were more polar than chloroform/methanol/water (1/1/1). The considerable water content of BEAsWat and BEDhpWat (0/1/1/1/) was 45.4 and 42.6% (w%) of hydrophilic organic phase, and 66.4 and 51.2% (w%) of salt-containing aqueous phase, respectively, closed to conventional aqueous two-phase system. Therefore, the polarity of HO/S TPS is in the middle of organic/aqueous and aqueous two-phase system. The LogKC values of twenty four polar compounds as model mixture confirmed that the polarities of HO/S TPSs were matched to that of the polar compounds and shown to be a very selective technique capable of separating positional isomers. Moreover, BEAsWat and BEDhpWat systems can be easily retained in CCC column with suitable elution mode. The hydrodynamic behavior reversion of HO/S TPS on hydrodynamic CCC was observed and was tentatively explained based on the density difference. Finally, caffeoylquinic acid isomers and dihydroxybenzoic acid isomers were successfully separated with HO/S TPS on CCC, respectively. Those results demonstrate that HO/S TPS on CCC is a performant and stable way to separate polar compounds from natural products.

  14. Chelate-Modified Fenton Reaction for the Degradation of Trichloroethylene in Aqueous and Two-Phase Systems

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, Scott [Univ of KY, dept of chemical and materials engineering; lynch, Andrew [Univ of KY, dept of chemical and materials engineering; Bachas, Leonidas [Univ of KY, Dept of Chemistry; hampson, Steve [Univ of KY Center for Applied Energy Research - KY Research Consortium of Energy and Environment; Ormsbee, Lindelle [Univ of KY Center for Applied Energy Research - KY Research Consortium of Energy and Environment; Bhattacharyya, Dibakar [Univ of KY, dept of chemical and materials engineering

    2008-06-01

    The Standard Fenton reaction has been used for In-Situ Chemical Oxidation (ISCO) of toxic organics in groundwater. However, it requires low pH operating conditions, and thus has limitations for in situ applications. In addition, hydroxyl radicals are rapidly consumed by hydroxyl scavengers found in the subsurface. These problems are alleviated through the chelate-modified Fenton (hydroxyl radical) reaction, which includes the addition of nontoxic chelate (L) such as citrate or gluconic acid. This chelate allows the reaction to take place at bear neutral pH and control hydrogen peroxide consumption by binding to Fe(II), forming an FeL complex. The chelate also binds to Fe(III), preventing its precipitation as ferric hydroxide and thus prevents problems associated with injection well plugging. The rate of TCE dechlorination in chelate-modified Fenton systems is a function of pH, H2O2 concentration, and FE:L ratio. The primary objective of this research is to model and apply this process to the destruction of trichloroethylene (TCE) present in both the aqueous and organic (in the form of droplets) phases. Experimentation proved the chelate-modified Fenton reaction effectively dechlorinates TCE in both the aqueous and organic phases at near-neutral pH. Other focuses of this work include determining the effect of [L]:[Fe] ratios on H2O2 and TCE degradation as well as reusability of the FE citrate solution under repeated H2O2 injections. Generalized models were developed to predict the concentration of TCE in the aqueous phase and TCE droplet radius as a function of time using established hydroxyl radial kinetics and mass transfer relationships.

  15. Liquid-liquid equilibrium and partitioning features of bovine trypsin in Ucon 50 HB5100 /sodium citrate aqueous two phase systems

    OpenAIRE

    Tubío, Gisela; Venâncio, Armando; J. A. Teixeira; Nerli, Bibiana B.; Picó, Guillermo A.

    2008-01-01

    The phase diagrams of Ucon 50-HB-5100, a non-ionic random copolymer of ethylene oxide and propylene oxide (EOPO) and sodium citrate aqueous two-phase systems were determined at different pHs (5.20 and 8.20) and temperatures (5, 20 and 40º C). The binodal curves were determined by refractive index and enzymatic assay of the solution and described using a four-parameter sigmoidal equation, the reliability of the measured tie line compositions was ascertained by correlation equations...

  16. A microdevice assisted approach for the preparation, characterization and selection of continuous aqueous two-phase systems: from micro to bench-scale.

    Science.gov (United States)

    Vázquez-Villegas, Patricia; Ouellet, Eric; González, Claudia; Ruiz-Ruiz, Federico; Rito-Palomares, Marco; Haynes, Charles A; Aguilar, Oscar

    2016-07-01

    Aqueous two-phase systems (ATPS) have emerged as an alternative strategy for the recovery and purification of a wide variety of biological products. Typical process development requires a large screening of experimental conditions towards industrial adoption where continuous processes are preferred. In this work, it was proved that under certain flow conditions, ATPS could be formed continuously inside a microchannel, starting from stocks of phase components. Staggered herringbone chaotic micromixers included within the device sequentially and rapidly prepare two-phase systems across an entire range of useful phase compositions. Two-phase diagrams (binodal curves) were easily plotted using the cloud-point method for systems of different components and compared with previously reported curves for each system, proving that phase formation inside the device correlated with the previously reported diagrams. A proof of concept for sample partitioning in such a microdevice was performed with two different experimental models: BSA and red blood cells. Finally, the microdevice was employed to obtain information about the recovery and partition coefficient of invertase from a real complex mixture of proteins (yeast extract) to design a process for the recovery of the enzyme selecting a suitable system and composition to perform the process at bench-scale. PMID:27302418

  17. Physicochemical characterization of novel aqueous two-phase system: gemini surfactant 12-2-12/NaBr/H2O.

    Science.gov (United States)

    Yue, Ling; He, Zimeng; Zhu, Yunfeng; Shang, Yazhuo; Liu, Honglai

    2015-04-01

    A novel aqueous two-phase system (ATPS) only containing Gemini surfactant ethanediyl-1,2-bis(dodecyldimethylammonium bromide) and an inorganic salt sodium bromide was designed, and the physicochemical properties of the ATPS were investigated systematically. The results have shown that the coexisting two phases, one surfactant-rich and the other salt-rich, are stable and the phase behavior, volume ratio, and extraction efficiency of ATPS are strongly influenced by contents of surfactant and salt. The novel ATPS here investigated have potential application in partitioning and analysis of biomaterials. Compared with other complicated surfactant-based ATPS, the surfactant concentration for the formation of ATPS is much lower, which implies that the studied system is potentially more economical for purification and separation of biomaterials. Meanwhile, the surfactant can be recycled by altering salt concentration in ATPS. Lyotropic liquid crystal was found in the bottom phase besides micelles under different conditions. The salting-out effect may be the driving force of ATPS formation for the studied "living polymer"/salt system. However, the coexistence of micelles with different microstructures is the necessary condition of phase separation. The current studies not only present a new ATPS for partitioning and analysis of biomaterials but also have a great significance on rational use of Gemini surfactants. PMID:25649445

  18. Calculation of liquid-liquid equilibrium of aqueous two-phase systems using a chemical-theory-based excess Gibbs energy model

    Directory of Open Access Journals (Sweden)

    Pessôa Filho P. A.

    2004-01-01

    Full Text Available Mixtures containing compounds that undergo hydrogen bonding show large deviations from ideal behavior. These deviations can be accounted for through chemical theory, according to which the formation of a hydrogen bond can be treated as a chemical reaction. This chemical equilibrium needs to be taken into account when applying stability criteria and carrying out phase equilibrium calculations. In this work, we illustrate the application of the stability criteria to establish the conditions under which a liquid-phase split may occur and the subsequent calculation of liquid-liquid equilibrium using a chemical-theory-modified Flory-Huggins equation to describe the non ideality of aqueous two-phase systems composed of poly(ethylene glycol and dextran. The model was found to be able to correlate ternary liquid-liquid diagrams reasonably well by simple adjustment of the polymer-polymer binary interaction parameter.

  19. Separation of clavulanic acid from fermented broth of amino acids by an aqueous two-phase system and ion-exchange adsorption.

    Science.gov (United States)

    da Silva, Clovis Sacardo; Cuel, Maressa Fabiano; Barreto, Verônica Orlandin; Kwong, Wu Hong; Hokka, Carlos O; Barboza, M

    2012-02-15

    The clavulanic acid is a substance which inhibits the β-lactamases used with penicillins for therapeutic treatment. After the fermentation, by-products of low molecular weight such as amino acids lysine, histidine, proline and tyrosine are present in the fermented broth. To remove these impurities the techniques of extraction by an aqueous two-phase system of 17% polyethylene glycol molecular weight 600 and 15% potassium phosphate were used for a partial purification. A subsequent ion-exchange adsorption was used for the recuperation of the clavulanic acid of the top phase and purification getting a concentration factor of 2 and purification of 100% in relation to the amino acids lysine, histidine, proline and tyrosine.

  20. An alternative method to isolate protease and phospholipase A2 toxins from snake venoms based on partitioning of aqueous two-phase systems

    Directory of Open Access Journals (Sweden)

    GN Gómez

    2012-01-01

    Full Text Available Snake venoms are rich sources of active proteins that have been employed in the diagnosis and treatment of health disorders and antivenom therapy. Developing countries demand fast economical downstream processes for the purification of this biomolecule type without requiring sophisticated equipment. We developed an alternative, simple and easy to scale-up method, able to purify simultaneously protease and phospholipase A2 toxins from Bothrops alternatus venom. It comprises a multiple-step partition procedure with polyethylene-glycol/phosphate aqueous two-phase systems followed by a gel filtration chromatographic step. Two single bands in SDS-polyacrylamide gel electrophoresis and increased proteolytic and phospholipase A2 specific activities evidence the homogeneity of the isolated proteins.

  1. Extraction of Theanine from Waste Liquid of Tea Polyphenol Production in Aqueous Two-phase Systems with Cationic and Anionic Surfactants

    Institute of Scientific and Technical Information of China (English)

    ZHANG Junwei; WANG Yan; PENG Qijun

    2013-01-01

    Extraction of theanine from waste liquid of tea polyphenol production was studied in aqueous surfactant two-phase system (ASTP) with cationic suffactant (CTAB) and anionic surfactant (SDS).Results indicate that the region of ASTP is narrow and there is only a two-phase region of cationic surfactant.The increase in concentrations of NaBr and Na2SO4 are beneficial to the formation of ASTP.Theanine concentration in the bottom phase increases with increasing concentration of theanine,whereas the partition coefficient and extraction rate only change a little when the concentration of theanine is above 0.2 g· L-1.With the increase of SDS concentration,the phase ratio and the partition coefficient decrease,while the extraction efficiency of theanine increases and the concentration of theaninc changes a little in the range from 2.4/7.5 to 2.8/7.2 for SDS/CTAB ratio.The temperature has a notable effect on the concentration of theanine in the bottom phase,partition coefficient and extraction rate of theanine.The increase of waste liquid decreases the phase ratio,increases the concentration and extraction rate of theanine in the bottom phase,since the protein and the saccharide enter the bottom phase with theanine.

  2. Separation of curcuminoids using ionic liquid based aqueous two-phase system coupled with in situ dispersive liquid-liquid microextraction.

    Science.gov (United States)

    Shu, Yang; Gao, Mingcen; Wang, Xueying; Song, Rusheng; Lu, Jun; Chen, Xuwei

    2016-01-01

    An aqueous two-phase extraction system (ATPS) combined with an in situ dispersive liquid-liquid microextraction (DLLME) method using imidazolium ionic liquids (ILs) for the separation of curcuminoids is developed. The influence of structure of IL, the type of metathesis reagents, and the back extraction agents on the extraction efficiency is investigated. 2.0mg of curcuminoids are extracted by an IL ATPS composed of 0.4g 1,3-diethylimidazolium iodine (EeimI), 0.6g potassium hydrogen phosphate, 1.0g water. Then the bis[(trifluoromethyl)sulfonyl]imide lithium (LiNTf2) aqueous solution is added to the EeimI-rich phase of the ATPS. The water-immiscible ionic liquids, 1,3-diethylimidazole bis[(trifluoromethyl)sulfonyl]imide (EeimNTf2), forms by the metathesis reaction. The in situ DLLME is triggered simultaneously and further purifies the curcuminoids. 92% of EeimI transforms into EeimNTf2 and thus the Eeim(+) cation is used for twice in this method. Finally, 0.1mol/L NaOH aqueous solution is used as the back extraction reagent. The curcuminoids precipitate is achieved with 93% of recovery when the aqueous solution is adjusted to pH 3.0. This ATPS-DLLME method is successfully applied to the separation of curcuminoids from Curcuma Longa (0.96±0.02% of extraction yield, a purity of >51% with respect to the total dry mass of the product).

  3. Prediction of liquid-liquid equilibria for polyethylene glycol based aqueous two-phase system by ASOG and UNIFAC method

    Directory of Open Access Journals (Sweden)

    M. Perumalsamy

    2009-03-01

    Full Text Available Liquid-Liquid equilibrium data were obtained for the polyethylene glycol2000(PEG2000-sodium citrate-water system at 298.15, 308.15 and 318.15 K. The effect of temperature on binodal and tie line data was studied and published in a previous article (Murugesan and Perumalsamy, 2005. The interaction parameters of ASOG and UNIFAC models were estimated using the LLE data of PEG2000-sodium citrate-water system and are used to predict the LLE data for PEG6000-sodium citrate-water system at 298.15, 308.15 and 318.15 K (literature data. The predicted LLE data by both ASOG and UNIFAC models showed good agreement with the experimental and literature data.

  4. 手性药物扁桃酸的双水相分离%Study on partition of D(-)-mandelic acid in aqueous two-phase systems

    Institute of Scientific and Technical Information of China (English)

    许小平; 李忠琴; 陈杰波

    2004-01-01

    Studies on the partition of D (-)-mandelic acid were performed in polyethylene glycol (PEG) with molecular masses of 2000, 4000, 6000, 10000, 20000- ammonium sulfate systems. The effect of various parameters such as molecular mass of PEG, phase composition, pH of the system and temperature were investigated in this work. The results indicate that the molecular mass of PEG is a key factor affecting the partitioning behaviors of D(-)-mandelic acid in the PEG -(NH4)2SO4 systems. The influence of pH on the partition shows that the partition coefficient of D(-)-mandelic acid decreases with the increase of pH value. D(-)-mandelic acid partition is only slightly influenced by the temperature. All these indicate that the aqueous two-phase is a very suitable alternative system for the separation of D(-)-mandelic acid.%采用聚乙二醇-硫酸铵双水相系统分离手性药物扁桃酸.研究了聚乙二醇分子量、相组成、pH值和温度对扁桃酸分离的影响.结果表明,聚乙二醇分子量对双水相分离扁桃酸的影响最大;温度对扁桃酸的分离几乎没有影响;随pH增大,扁桃酸分配系数减少.

  5. Direct Purification of Pectinase from Mango (Mangifera Indica Cv. Chokanan Peel Using a PEG/Salt-Based Aqueous Two Phase System

    Directory of Open Access Journals (Sweden)

    Abdul Manap Mohd Yazid

    2011-10-01

    Full Text Available An Aqueous Two-Phase System (ATPS was employed for the first time for the separation and purification of pectinase from mango (Mangifera Indica Cv. Chokanan peel. The effects of different parameters such as molecular weight of the polymer (polyethylene glycol, 2,000–10,000, potassium phosphate composition (12–20%, w/w, system pH (6–9, and addition of different concentrations of neutral salts (0–8%, w/w on partition behavior of pectinase were investigated. The partition coefficient of the enzyme was decreased by increasing the PEG molecular weight. Additionally, the phase composition showed a significant effect on purification factor and yield of the enzyme. Optimum conditions for purification of pectinase from mango peel were achieved in a 14% PEG 4000-14% potassium phosphate system using 3% (w/w NaCl addition at pH 7.0. Based on this system, the purification factor of pectinase was increased to 13.2 with a high yield of (97.6%. Thus, this study proves that ATPS can be an inexpensive and effective method for partitioning of pectinase from mango peel.

  6. Aqueous two-phase system cold-set gelation using natural and recombinant probiotic lactic acid bacteria as a gelling agent.

    Science.gov (United States)

    Léonard, Lucie; Husson, Florence; Langella, Philippe; Châtel, Jean-Marc; Saurel, Rémi

    2016-05-01

    The present study aimed to entrap probiotic lactic acid bacteria (LAB) in a sodium alginate and sodium caseinate aqueous two-phase gel system. The natural acidifying properties of two therapeutic probiotic LAB were exploited to liberate calcium ions progressively from calcium carbonate (CaCO3), which caused the gelation of the co-existing phases. Bi-biopolymeric matrix gelation of GDL/CaCO3 or LAB/CaCO3 was monitored by dynamic rheological measurements, and the final gels were characterized by frequency dependence measurements and confocal laser scanning microscopy. Weak to strong gels were formed with an elastic modulus G' from 10 to 1.000Pa, respectively. After cold-set gelation of our system, confocal laser scanning microscopy showed spherical protein microdomains trapped within a calcium alginate network. LAB cells were stained to study their partition in the self-gelling matrices. Our LAB strains showed two different behaviors, which may relate to the exopolysaccharide production: (i) Lactobacillus plantarum CNRZ1997 cells were found mainly in continuous alginate networks, whereas (ii) Lactococcus lactis cells were localized in protein microdomains. This alginate-caseinate phase-separated system that was self-gelled by LAB cells may be an innovative approach for immobilizing and protecting LAB cells. PMID:26874119

  7. A novel aqueous micellar two-phase system composed of surfactant and sorbitol for purification of pectinase enzyme from Psidium guajava and recycling phase components.

    Science.gov (United States)

    Amid, Mehrnoush; Murshid, Fara Syazana; Manap, Mohd Yazid; Hussin, Muhaini

    2015-01-01

    A novel aqueous two-phase system composed of a surfactant and sorbitol was employed for the first time to purify pectinase from Psidium guajava. The influences of different parameters, including the type and concentration of the surfactant and the concentration and composition of the surfactant/sorbitol ratio, on the partitioning behavior and recovery of pectinase were investigated. Moreover, the effects of system pH and the crude load on purification fold and the yield of purified pectinase were studied. The experimental results indicated that the pectinase was partitioned into surfactant-rich top phase, and the impurities were partitioned into the sorbitol-rich bottom phase with the novel method involving an ATPS composed of 26% (w/w) Triton X-100 and 23% (w/w) sorbitol at 54.2% of the TLL crude load of 20% (w/w) at pH 6.0. The enzyme was successfully recovered by this method with a high purification factor of 15.2 and a yield of 98.3%, whereas the phase components were also recovered and recycled at rates above 96%. This study demonstrated that this novel ATPS method can be used as an efficient and economical alternative to the traditional ATPS for the purification and recovery of the valuable enzyme.

  8. Extraction protease expressed by Penicillium fellutanum from the Brazilian savanna using poly(ethylene glycol)/sodium polyacrylate/NaCl aqueous two-phase system.

    Science.gov (United States)

    Barros, Kleber V G; Souza, Paula M; Cardoso, Samuel L; Borges, Leonardo L; Filho, Edivaldo X F; Junior, Adalberto P; Magalhães, Pérola O

    2015-01-01

    The partitioning of protease expressed by Penicillium fellutanum from the Brazilian savanna in a novel inexpensive and stable aqueous two-phase system (ATPS) composed of poly(ethylene glycol) (PEG) and sodium polyacrylate (NaPA) was studied in this work using factorial design. The ATPS is formed by mixing both polymers with a salt (NaCl) and fermented broth of P. fellutanum. The effects of molar mass (2,000, 4,000, and 6,000 g ⋅ mol(-1)) and concentration (6, 8, and 10 wt%) of PEG and that of NaPA concentration (6, 8, and 10 wt%) on protease partitioning (K) at 25 °C were studied. A two-level factorial design (2(3)) was implemented. The effect of Na2 SO4 concentration (5, 10, and 15 wt%) on the reextraction of the enzyme was also analyzed. The partition coefficient K ranged from 77.51 to 1.21, indicating the versatility of the method. The reextraction was achieved with the addition of 5% Na2 SO4 , allowing the partitioning of the protease to the upper phase, whereas total proteins were directed to the bottom phase. The results of partitioning using the PEG/NaPA/NaCl system and that of the subsequent reextraction with Na2 SO4 suggest that this method can be used to purify proteases from fermented broth of P. fellutanum. PMID:25546578

  9. A Novel Aqueous Micellar Two-Phase System Composed of Surfactant and Sorbitol for Purification of Pectinase Enzyme from Psidium guajava and Recycling Phase Components

    Directory of Open Access Journals (Sweden)

    Mehrnoush Amid

    2015-01-01

    Full Text Available A novel aqueous two-phase system composed of a surfactant and sorbitol was employed for the first time to purify pectinase from Psidium guajava. The influences of different parameters, including the type and concentration of the surfactant and the concentration and composition of the surfactant/sorbitol ratio, on the partitioning behavior and recovery of pectinase were investigated. Moreover, the effects of system pH and the crude load on purification fold and the yield of purified pectinase were studied. The experimental results indicated that the pectinase was partitioned into surfactant-rich top phase, and the impurities were partitioned into the sorbitol-rich bottom phase with the novel method involving an ATPS composed of 26% (w/w Triton X-100 and 23% (w/w sorbitol at 54.2% of the TLL crude load of 20% (w/w at pH 6.0. The enzyme was successfully recovered by this method with a high purification factor of 15.2 and a yield of 98.3%, whereas the phase components were also recovered and recycled at rates above 96%. This study demonstrated that this novel ATPS method can be used as an efficient and economical alternative to the traditional ATPS for the purification and recovery of the valuable enzyme.

  10. PEG-salt aqueous two-phase systems: an attractive and versatile liquid-liquid extraction technology for the downstream processing of proteins and enzymes.

    Science.gov (United States)

    Glyk, Anna; Scheper, Thomas; Beutel, Sascha

    2015-08-01

    Nowadays, there is an increasing demand to establish new feasible, efficient downstream processing (DSP) techniques in biotechnology and related fields. Although several conventional DSP technologies have been widely employed, they are usually expensive and time-consuming and often provide only low recovery yields. Hence, the DSP is one major bottleneck for the commercialization of biological products. In this context, polyethylene glycol (PEG)-salt aqueous two-phase systems (ATPS) represent a promising, efficient liquid-liquid extraction technology for the DSP of various biomolecules, such as proteins and enzymes. Furthermore, ATPS can overcome the limitations of traditional DSP techniques and have gained importance for applications in several fields of biotechnology due to versatile advantages over conventional DSP methods, such as biocompatibility, technical simplicity, and easy scale-up potential. In the present review, various practical applications of PEG-salt ATPS are presented to highlight their feasibility to operate as an attractive and versatile liquid-liquid extraction technology for the DSP of proteins and enzymes, thus facilitating the approach of new researchers to this technique. Thereby, single- and multi-stage extraction, several process integration methods, as well as large-scale extraction and purification of proteins regarding technical aspects, scale-up, recycling of process chemicals, and economic aspects are discussed.

  11. Interrelationship between partition behavior of organic compounds and proteins in aqueous dextran-polyethylene glycol and polyethylene glycol-sodium sulfate two-phase systems.

    Science.gov (United States)

    Ferreira, Luisa A; da Silva, Nuno R; Wlodarczyk, Samarina R; Loureiro, Joana A; Madeira, Pedro P; Teixeira, José A; Uversky, Vladimir N; Zaslavsky, Boris Y

    2016-04-22

    Partition behavior of adenosine and guanine mononucleotides was examined in aqueous dextran-polyethylene glycol (PEG) and PEG-sodium sulfate two-phase systems. The partition coefficients for each series of mononucleotides were analyzed as a functions of the number of phosphate groups and found to be dependent on the nature of nucleic base and on the type of ATPS utilized. It was concluded that an average contribution of a phosphate group into logarithm of partition coefficient of a mononucleotide cannot be used to estimate the difference between the electrostatic properties of the coexisting phases of ATPS. The data obtained in this study were considered together with those for other organic compounds and proteins reported previously, and the linear interrelationship between logarithms of partition coefficients in dextran-PEG, PEG-Na2SO4 and PEG-Na2SO4-0.215M NaCl (all in 0.01M Na- or K/Na-phosphate buffer, pH 7.4 or 6.8) was established. Similar relationship was found for the previously reported data for proteins in Dex-PEG, PEG-600-Na2SO4, and PEG-8000-Na2SO4 ATPS. It is suggested that the linear relationships of the kind established in ATPS may be observed for biological properties of compounds as well.

  12. Ionic liquid-based ultrasound-assisted extraction and aqueous two-phase system for analysis of caffeoylquinic acids from Flos Lonicerae Japonicae.

    Science.gov (United States)

    Tan, Ting; Lai, Chang-Jiang-Sheng; OuYang, Hui; He, Ming-Zhen; Feng, Yulin

    2016-02-20

    In this work, an ionic liquid-based ultrasonic-assisted extraction (ILUAE) method was developed to extract caffeoylquinic acids (CQAs) from Flos Lonicerae Japonicae (FLJ). ILUAE parameters were optimized by response surface methodology, including IL concentration, ultrasonic time, and liquid-solid ratio. Optimized ILUAE approach gained the highest extraction yields of 28.53, 18.21, 3.84mg/g for 3-O-caffeoylquinic acid (C1), 3,5-di-O-caffeoylquinic acid (C2), 3,4-di-O-caffeoylquinic acid (C3), respectively. C1-C3 are the three most abundant CQAs compounds in FLJ. The method showed comparable extraction yield and shorter extraction time compared with conventional extraction techniques. Subsequently, an aqueous two-phase system (ATPS) was applied in extraction solutions. Two trace CQAs, 5-O-caffeoylquinic acid (C4) and 4,5-di-O-caffeoylquinic acid (C5), were significantly enriched with signal to noise values increasing from less than 10 to higher than 1475. The results indicated that ILUAE and ATPS are efficient and environmentally-friendly sample extraction and enrichment techniques for CQAs from herbal medicines. PMID:26730510

  13. Separation of Cd and Ni from Ni-Cd batteries by an environmentally safe methodology employing aqueous two-phase systems

    Energy Technology Data Exchange (ETDEWEB)

    Lacerda, Vania Goncalves; Mageste, Aparecida Barbosa; Santos, Igor Jose Boggione; da Silva, Luis Henrique Mendes; da Silva, Maria do Carmo Hespanhol [Grupo de Quimica Verde Coloidal e Macromolecular, Departamento de Quimica, Centro de Ciencias e Tecnologicas, Universidade Federal de Vicosa, Av. P.H. Rolfs s/n, Campus da UFV, Vicosa, 36570-000 (Brazil)

    2009-09-05

    The separation of Cd and Ni from Ni-Cd batteries using an aqueous two-phase system (ATPS) composed of copolymer L35, Li{sub 2}SO{sub 4} and water is investigated. The extraction behavior of these metals from the bottom phase (BP) to the upper phase (UP) of the ATPS is affected by the amount of added extractant (potassium iodide), tie-line length (TLL), mass ratio between the phases of the ATPS, leaching and dilution factor of the battery samples. Maximum extraction of Cd (99.2 {+-} 3.1)% and Ni (10.6 {+-} 0.4)% is obtained when the batteries are leached with HCl, under the following conditions: 62.53% (w/w) TLL, concentration of KI equal to 50.00 mmol kg{sup -1}, mass ratio of the phases equal to 0.5 and a dilution factor of battery samples of 35. This novel methodology is efficient to separate the metals in question, with the advantage of being environmentally safe, since water is the main constituent of the ATPS, which is prepared with recyclable and biodegradable compounds. (author)

  14. Interrelationship between partition behavior of organic compounds and proteins in aqueous dextran-polyethylene glycol and polyethylene glycol-sodium sulfate two-phase systems.

    Science.gov (United States)

    Ferreira, Luisa A; da Silva, Nuno R; Wlodarczyk, Samarina R; Loureiro, Joana A; Madeira, Pedro P; Teixeira, José A; Uversky, Vladimir N; Zaslavsky, Boris Y

    2016-04-22

    Partition behavior of adenosine and guanine mononucleotides was examined in aqueous dextran-polyethylene glycol (PEG) and PEG-sodium sulfate two-phase systems. The partition coefficients for each series of mononucleotides were analyzed as a functions of the number of phosphate groups and found to be dependent on the nature of nucleic base and on the type of ATPS utilized. It was concluded that an average contribution of a phosphate group into logarithm of partition coefficient of a mononucleotide cannot be used to estimate the difference between the electrostatic properties of the coexisting phases of ATPS. The data obtained in this study were considered together with those for other organic compounds and proteins reported previously, and the linear interrelationship between logarithms of partition coefficients in dextran-PEG, PEG-Na2SO4 and PEG-Na2SO4-0.215M NaCl (all in 0.01M Na- or K/Na-phosphate buffer, pH 7.4 or 6.8) was established. Similar relationship was found for the previously reported data for proteins in Dex-PEG, PEG-600-Na2SO4, and PEG-8000-Na2SO4 ATPS. It is suggested that the linear relationships of the kind established in ATPS may be observed for biological properties of compounds as well. PMID:27016118

  15. Application of an aqueous two-phase micellar system to extract bromelain from pineapple (Ananas comosus) peel waste and analysis of bromelain stability in cosmetic formulations.

    Science.gov (United States)

    Spir, Lívia Genovez; Ataide, Janaína Artem; De Lencastre Novaes, Letícia Celia; Moriel, Patrícia; Mazzola, Priscila Gava; De Borba Gurpilhares, Daniela; Silveira, Edgar; Pessoa, Adalberto; Tambourgi, Elias Basile

    2015-01-01

    Bromelain is a set of proteolytic enzymes found in pineapple (Ananas comosus) tissues such as stem, fruit and leaves. Because of its proteolytic activity, bromelain has potential applications in the cosmetic, pharmaceutical, and food industries. The present study focused on the recovery of bromelain from pineapple peel by liquid-liquid extraction in aqueous two-phase micellar systems (ATPMS), using Triton X-114 (TX-114) and McIlvaine buffer, in the absence and presence of electrolytes CaCl2 and KI; the cloud points of the generated extraction systems were studied by plotting binodal curves. Based on the cloud points, three temperatures were selected for extraction: 30, 33, and 36°C for systems in the absence of salts; 40, 43, and 46°C in the presence of KI; 24, 27, and 30°C in the presence of CaCl2 . Total protein and enzymatic activities were analyzed to monitor bromelain. Employing the ATPMS chosen for extraction (0.5 M KI with 3% TX-114, at pH 6.0, at 40°C), the bromelain extract stability was assessed after incorporation into three cosmetic bases: an anhydrous gel, a cream, and a cream-gel formulation. The cream-gel formulation presented as the most appropriate base to convey bromelain, and its optimal storage conditions were found to be 4.0 ± 0.5°C. The selected ATPMS enabled the extraction of a biomolecule with high added value from waste lined-up in a cosmetic formulation, allowing for exploration of further cosmetic potential. PMID:25919128

  16. An Aqueous Two-Phase System for the Concentration and Extraction of Proteins from the Interface for Detection Using the Lateral-Flow Immunoassay.

    Directory of Open Access Journals (Sweden)

    Ricky Y T Chiu

    Full Text Available The paper-based immunoassay for point-of-care diagnostics is widely used due to its low cost and portability over traditional lab-based assays. Lateral-flow immunoassay (LFA is the most well-established paper-based assay since it is rapid and easy to use. However, the disadvantage of LFA is its lack of sensitivity in some cases where a large sample volume is required, limiting its use as a diagnostic tool. To improve the sensitivity of LFA, we previously reported on the concentration of analytes into one of the two bulk phases of an aqueous two-phase system (ATPS prior to detection. In this study, we preserved the advantages of LFA while significantly improving upon our previous proof-of-concept studies by employing a novel approach of concentrating gold nanoparticles, a common LFA colorimetric indicator. By conjugating specific antibodies and polymers to the surfaces of the particles, these gold nanoprobes (GNPs were able to capture target proteins in the sample and subsequently be concentrated within 10 min at the interface of an ATPS solution comprised of polyethylene glycol, potassium phosphate, and phosphate-buffered saline. These GNPs were then extracted and applied directly to LFA. By combining this prior ATPS interface extraction with LFA, the detection limit of LFA for a model protein was improved by 100-fold from 1 ng/μL to 0.01 ng/μL. Additionally, we examined the behavior of the ATPS system in fetal bovine serum and synthetic urine to more closely approach real-world applications. Despite using more complex matrices, ATPS interface extraction still improved the detection limit by 100-fold within 15 to 25 min, demonstrating the system's potential to be applied to patient samples.

  17. Optimization of Serine Protease Purification from Mango (Mangifera indica cv. Chokanan Peel in Polyethylene Glycol/Dextran Aqueous Two Phase System

    Directory of Open Access Journals (Sweden)

    Abdul Manap Mohd Yazid

    2012-03-01

    Full Text Available Mango peel is a good source of protease but remains an industrial waste. This study focuses on the optimization of polyethylene glycol (PEG/dextran-based aqueous two-phase system (ATPS to purify serine protease from mango peel. The activity of serine protease in different phase systems was studied and then the possible relationship between the purification variables, namely polyethylene glycol molecular weight (PEG, 4000–12,000 g·mol−1, tie line length (−3.42–35.27%, NaCl (−2.5–11.5% and pH (4.5–10.5 on the enzymatic properties of purified enzyme was investigated. The most significant effect of PEG was on the efficiency of serine protease purification. Also, there was a significant increase in the partition coefficient with the addition of 4.5% of NaCl to the system. This could be due to the high hydrophobicity of serine protease compared to protein contaminates. The optimum conditions to achieve high partition coefficient (84.2 purification factor (14.37 and yield (97.3% of serine protease were obtained in the presence of 8000 g·mol−1 of PEG, 17.2% of tie line length and 4.5% of NaCl at pH 7.5. The enzymatic properties of purified serine protease using PEG/dextran ATPS showed that the enzyme could be purified at a high purification factor and yield with easy scale-up and fast processing.

  18. Two-phase flow in refrigeration systems

    CERN Document Server

    Gu, Junjie; Gan, Zhongxue

    2013-01-01

    Two-Phase Flow in Refrigeration Systems presents recent developments from the authors' extensive research programs on two-phase flow in refrigeration systems. This book covers advanced mass and heat transfer and vapor compression refrigeration systems and shows how the performance of an automotive air-conditioning system is affected through results obtained experimentally and theoretically, specifically with consideration of two-phase flow and oil concentration. The book is ideal for university postgraduate students as a textbook, researchers and professors as an academic reference book, and b

  19. Extraction and Purification of Quercitrin, Hyperoside, Rutin, and Afzelin from Zanthoxylum Bungeanum Maxim Leaves Using an Aqueous Two-Phase System.

    Science.gov (United States)

    He, Fengyuan; Li, Dengwu; Wang, Dongmei; Deng, Ming

    2016-07-01

    In this study, an aqueous two-phase system (ATPS) based on ethanol/NaH2 PO4 was developed for the extraction and purification of quercitrin, hyperoside, rutin, and afzelin from Zanthoxylum bungeanum Maxim leaves. These 4 flavonoids were 1st extracted from dried Z. bungeanum leaves using a 60% ethanol solution and subsequently added to the ATPS for further purification. The partition behavior of the 4 flavonoids in ATPS was investigated. The optimal ATPS conditions were: 29% (w/w) NaH2 PO4 , 25% (w/w) ethanol concentration, 1% (w/w) added amount of leaf extracts, no pH adjustment, and repeated 1 h extractions at 25 °C. Under the optimal conditions for the 10 g ATPS, the absolute recovery of quercitrin, hyperoside, rutin, and afzelin reached 90.3%, 83.5%, 92.3%, and 89.1%, respectively. Compared to the 60% ethanol extracts, the content of quercitrin (44.8 mg/g), hyperoside (65.6 mg/g), rutin (56.4 mg/g), and afzelin (6.84 mg/g) in the extracts increased by 49.9%, 38.8%, 45.6%, and 36.8% respectively. The extracts after ATPS also exhibited stronger antioxidant activities, the 2,2-diphenyl-1-picrylhydrazyl IC50 value (10.5 μg/mL) decreased by 41.8%, and the 2,2-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt value (966 μmol Trolox/g) and ferric reducing power value (619 μmol Trolox/g) increased by 29.8% and 53.7%, respectively. Furthermore, scale-up experiments indicated that a larger scale experiment was feasible for the purification of the 4 flavonoids. PMID:27240023

  20. A method for dye extraction using an aqueous two-phase system: Effect of co-occurrence of contaminants in textile industry wastewater.

    Science.gov (United States)

    Borges, Gabriella Alexandre; Silva, Luciana Pereira; Penido, Jussara Alves; de Lemos, Leandro Rodrigues; Mageste, Aparecida Barbosa; Rodrigues, Guilherme Dias

    2016-12-01

    This paper reports a green and efficient procedure for extraction of the dyes Malachite Green (MG), Methylene Blue (MB), and Reactive Red 195 (RR) using an aqueous two-phase system (ATPS). An ATPS consists mainly of water, together with polymer and salt, and does not employ any organic solvent. The extraction efficiency was evaluated by means of the partition coefficients (K) and residual percentages (%R) of the dyes, under different experimental conditions, varying the tie-line length (TLL) of the system, the pH, the type of ATPS-forming electrolyte, and the type of ATPS-forming polymer. For MG, the best removal (K = 4.10 × 10(4), %R = 0.0069%) was obtained with the ATPS: PEO 1500 + Na2C4H4O6 (TLL = 50.21% (w/w), pH = 6.00). For MB, the maximum extraction (K = 559.9, %R = 0.258%) was achieved with the ATPS: PEO 400 + Na2SO4 (TLL = 50.31% (w/w), pH = 1.00). Finally for RR, the method that presented the best results (K = 3.75 × 10(4), %R = 0.237%) was the ATPS: PEO 400 + Na2SO4 (TLL = 50.31% (w/w), pH = 6.00). The method was applied to the recovery of these dyes from a textile effluent sample, resulting in values of K of 1.17 × 10(4), 724.1, and 3.98 × 10(4) for MG, MB, and RR, respectively, while the corresponding %R values were 0.0038, 0.154, and 0.023%, respectively. In addition, the ATPS methodology provided a high degree of color removal (96.5-97.95%) from the textile effluent.

  1. A method for dye extraction using an aqueous two-phase system: Effect of co-occurrence of contaminants in textile industry wastewater.

    Science.gov (United States)

    Borges, Gabriella Alexandre; Silva, Luciana Pereira; Penido, Jussara Alves; de Lemos, Leandro Rodrigues; Mageste, Aparecida Barbosa; Rodrigues, Guilherme Dias

    2016-12-01

    This paper reports a green and efficient procedure for extraction of the dyes Malachite Green (MG), Methylene Blue (MB), and Reactive Red 195 (RR) using an aqueous two-phase system (ATPS). An ATPS consists mainly of water, together with polymer and salt, and does not employ any organic solvent. The extraction efficiency was evaluated by means of the partition coefficients (K) and residual percentages (%R) of the dyes, under different experimental conditions, varying the tie-line length (TLL) of the system, the pH, the type of ATPS-forming electrolyte, and the type of ATPS-forming polymer. For MG, the best removal (K = 4.10 × 10(4), %R = 0.0069%) was obtained with the ATPS: PEO 1500 + Na2C4H4O6 (TLL = 50.21% (w/w), pH = 6.00). For MB, the maximum extraction (K = 559.9, %R = 0.258%) was achieved with the ATPS: PEO 400 + Na2SO4 (TLL = 50.31% (w/w), pH = 1.00). Finally for RR, the method that presented the best results (K = 3.75 × 10(4), %R = 0.237%) was the ATPS: PEO 400 + Na2SO4 (TLL = 50.31% (w/w), pH = 6.00). The method was applied to the recovery of these dyes from a textile effluent sample, resulting in values of K of 1.17 × 10(4), 724.1, and 3.98 × 10(4) for MG, MB, and RR, respectively, while the corresponding %R values were 0.0038, 0.154, and 0.023%, respectively. In addition, the ATPS methodology provided a high degree of color removal (96.5-97.95%) from the textile effluent. PMID:27591846

  2. EFFECT OF ALCOHOL ON AQUEOUS TWO-PHASE SYSTEM PROPERTIES OF SDS/CTAB/H2O/Na2SO4 SYSTEM%醇对正负离子表面活性剂双水相性质的影响

    Institute of Scientific and Technical Information of China (English)

    滕弘霓; 王利

    2004-01-01

    The effect of alcohol on the aqueous two-phase system properties of SDS/CTAB/H2O/Na2SO4 system was studied by the pseudo ternary phase diagram. The electrostatic forces (both attraction and repulsion) between cationic surfactant and anionic surfactant decreased because of the interaction of alcohol hydroxyl group and surfactant polar group. As a result, the phase area width of aqueous two-phase system increased. Long chain alcohol (more than five carbonatoms), which was in high concentration in the SDS/CTAB/H2O/Na2SO4) system, caused the anionic aqueous two-phase system area to vanish and the cationic aqueous two-phase system area to become wider. The CTAB rich phase turned from top phase to bottom phase.

  3. Partition of proteins in aqueous two-phase systems based on Cashew-nut tree gum and poly(ethylene glycol

    Directory of Open Access Journals (Sweden)

    Leonie Asfora Sarubbo

    2004-09-01

    Full Text Available The partitioning of two proteins, bovine serum albumin (BSA and trypsin was studied in an aqueous poly(ethylene glycol(PEG- Cashew-nut tree gum system. The phase diagram was provided for Cashew-nut tree gum and PEG molecular weight of 1500 at two different temperatures. The influence of several parameters including concentrations of polymers, pH, salt addition and temperature on the partitioning of these proteins were investigated.. The results of this research demonstrated the importance of the protein characteristics for partitioning in aqueous biphasic system.A partição de duas proteínas, albumina de soro bovino (BSA e tripsina foi estudada no sistema bifásico aquoso Polietileno glicol(PEG - Goma do cajueiro. O diagrama de fases foi estabelecido para a Goma do Cajueiro e para PEG de peso molecular 1500 em duas diferentes temperaturas. A influência de vários parâmetros na partição destas proteínas, incluindo concentração dos polímeros, pH, adição de sal e temperatura foi investigada. Os resultados desta pesquisa demonstraram a importância das características da proteína na partição em sistemas bifásicos aquosos.

  4. 黄芩甙在EOPO/盐双水相系统中的分配系数测定及关联%Measurement and Correlation of Partition Coefficients of Baicalin in EOPO/Salt Aqueous Two-Phase Systems

    Institute of Scientific and Technical Information of China (English)

    李伟; 朱自强

    2002-01-01

    The partition coefficients of baicalin were measured in ethylene oxide and propylene oxide (EOPO)/salt aqueous two-phase systemsat 298.15K. It was found that most of baicalin partitioned into EOPO-rich phase. The partition coefficients of baicalin varied from 10 to 120.The effect of various factors, including tie-line length, salt composition, molecular weight of EOPO, and solution pH, on the partition behaviorwas investigated in EOPO/salt systems. Furthermore the partition coefficients of baicalin were correlated using the modified Diamond-Hsumodel. Good agreement with experimental data is obtained. The average relative deviations are less than 5.0%.

  5. Study on aqueous two-phase extraction of L-phenylalanine by polyethylene glycol/salt system%聚乙二醇/盐双水相萃取L-苯丙氨酸的研究

    Institute of Scientific and Technical Information of China (English)

    孙晨; 刘文举; 刘宁宁

    2012-01-01

    研究了聚乙二醇/盐双水相体系的成相行为及L-苯丙氨酸在双水相中的分配规律,其中包括聚乙二醇的分子量、聚乙二醇质量分数、盐的种类及加入量、L-苯丙氨酸初始浓度和pH对萃取分离的影响。当聚乙二醇1000的质量分数为27%,磷酸氢二钾的质量浓度为O.15g/mL,L-苯丙氨酸的质量浓度为10g/L,体系的pH为8.5时,L-苯丙氨酸的萃取率最高为99.5%,分配系数最大为186.5。%An aqueous two- phase system of polyethylene glycol (PEG)/salt with the behavior of forming aqueous two-phase and the distribution rules of L-phenylalanine in the aqueous two-phase system were studied.Effects of the molecular weight of polyethylene glycol ,the mass fraction of polyethylene glycol ,the types and concentrations of salts,the initial concentration of L-phenylalanine and pH value were investigated.When the mass fraction of PEG1000 was 27% ,the mass concentration of K2HPO4was 0.]5g/mL,the initial concentration of L-phenylalanine was 10g/L and pH value was about 8.5,the highest extraction yield of L-phenylalanine could reach 99.5 %, partition coefficient of L-phenylalanine could reach 186.5.

  6. Pectinases partitioning in aqueous two-phase systems: an integration of the systems poly(ethylene glycol/crude dextran and poly(ethylene glycol/ammonium sulphate

    Directory of Open Access Journals (Sweden)

    STANA N. PEJIN

    2004-04-01

    Full Text Available The partitioning of pectinases in the poly(ethylene glucol4000/ammonium sulpohate system was studied and also its application for enzymes extraction from the top phase of the poly(ethylene glucol4000/crude dextran system. Almost complete one-sided partition of endo-pectinase and exo-pectinase to the bottom phase of the polymer/salt system was achieved at a tie-line length of 37.16 %. The concentration factors were 1.73 and 3.25, respectively. The highest total endo- and exo-pectinase yields (72.41 % and 69.46 %, respectively were obtained by integration of the polymer/polymer system at a tie-line of 8.61 % and a high phase volume ratio and the polymer/salt system at a tie-line of 30.23 % and a low phase volume ratio. Integration of the partitioning at a high tie-line length in the polymer/polimer and a low tie-line length in the polymer/salt system resulted in a total concentration factor of 1.5 and a purification of 1.66 fold for exo-pectinase. The addition of phosphate to this integrated system improved the total concentration factor and purification fold of the activity to 1.73 and 2.14, respectively.

  7. Extraction of doxycycline hydrochloride using anhydrous alcohol and acetone binary aqueous two phase system%醇和小分子有机物二元双水相体系萃取盐酸多西环素

    Institute of Scientific and Technical Information of China (English)

    关卫省; 邓江华; 韩娟

    2012-01-01

    基于小分子醇双水相体系和小分子有机物双水相体系,建立了乙醇与丙酮和( NH4) 2SO4形成的二元双水相体系萃取盐酸多西环素的新方法.研究了(NH4)2SO4浓度、pH值、温度、乙醇与丙酮用量和盐酸多西环素浓度对盐酸多西环素分配行为的影响.结果表明,体系的(NH4)2SO4浓度为41%,pH值在4.5 ~5.0,温度25℃,且盐酸多西环素的质量浓度70 mg/L时,萃取率可达93.61%,分配系数可达83.081.%Based on the molecular alcohol aqueous two-phase system and the small molecular organic two-phase system,the new method of using anhydrous alcohol and small molecular organic (acetone) with ( NH4)2SO4 binary aqueous two phase system for extracting doxycycline hydrochloride was set up. The influence factors on partition behaviors of doxycycline hydrochloride were studied, including the concentration of (NH4)2SO4,anhydrous alcohol and acetone consumption,pH value,temperature and doxycycline hydrochloride. The results showed that when (NH4)2SO4 concentration of 41% ,pH value of 4.5~5.0, and the temperature of 25℃ ,mass concentration of doxycycline hydrochloride 70 mg/L,the extraction rate up to 93.61% and 83.081 .respectively.

  8. Extraction of Doxycycline Hydrochloride Using Alcohol and Ionic Liquid Binary Aqueous Two Phase System%醇与离子液体二元双水相体系萃取盐酸多西环素

    Institute of Scientific and Technical Information of China (English)

    关卫省; 黎文娟; 韩娟

    2012-01-01

    Based on the molecular alcohol aqueous two-phase system and the ionic liquid aqueous two-phase system, the new method of using n-propanol and hydrophilic ionic liquid(1-butyl-3-methylimidazolium tetrafluoroborate, [Bmim]BF4) with (NH4)2SO4 binary aqueous two phase system for the extraction of doxycycline hydrochloride was developed. The influence factors on partition behaviors of doxycycline hydrochloride were studied, including concentration of (NH4)2SO4, n-propanol con-sumption, pH value, concentration of ionic liquid and doxycycline hydrochloride. The results showed that when using pH value of 4. 0 - 5. 0, (NH4) 2SO4 concentration of 34% and doxycycline hydrochloride concentration between 25 -95 mg/L, the extraction rate and distribution coefficient of doxycycline hydrochloride will be up to 90. 26% -95. 71% and 62. 452 - 149. 401, respectively.%基于小分子醇双水相体系和离子液体双水相体系,建立了正丙醇与亲水性离子液体1-丁基-3-甲基咪唑四氟硼酸[ Bmim]BF4和(NH4 )2SO4形成的二元双水相体系萃取盐酸多西环素的新方法.考察了(NH4)2SO4含量、正丙醇用量、pH值、离子液体含量以及盐酸多西环素含量对盐酸多西环素分配行为的影响.结果表明:当醇和离子液体二元双水相体系的pH值在4.0~5.0范围内,(NH4)2SO4含量为34%,且盐酸多西环素的质量浓度在25 ~ 95 mg/L之间时,该体系对盐酸多西环素的萃取率可达90.26% ~95.71%,分配系数可达62.452 ~ 149.401.

  9. [Bmim]Cl双水相体系对猪皮皮粉溶解性能的研究%The Dissolvability of Pigskin Hide Powder in the [Bmim] Cl Aqueous Two-phase System

    Institute of Scientific and Technical Information of China (English)

    邹永鹏; 刘森; 冯健; 华坚; 周华龙

    2012-01-01

    实验以溴代正丁烷和N-甲基咪唑为原料,丙酮为溶剂合成目标离子液体氯化1-丁基-3-甲基咪唑([Bmim]Cl).将合成的[Bmim]Cl、盐和去离子水混合形成离子液体双水相体系,并溶解猪皮皮粉.讨论不同种类的盐和不同质量分数的猪皮皮粉溶于猪皮皮粉溶于离子液体双水相体系的溶解情况.通过研究发现双水相体系中,盐为K2HPO4且浓度为65.5mg/mL时溶解猪皮胶原情况最好,平且当猪皮皮粉的质量分数为10%时,溶液已经达到饱和.用傅里叶红外光谱仪对回收的离子液体以及猪皮胶原再生膜进行红外分析,观察得到回收的离子液体的较好,猪皮皮粉溶解前后胶原二级结构未发生变化.%[Bmim]Cl was synthesized by n-butyl bromide and N-methylimidazole, with acetone as the solvent. [Bmim] Cl, salt and deionized water were mixed to form ionic liquids aqueous two-phase system which dissolved pigskin hide powder. The different kinds of salt and the different mass fraction pigskin hide powder were studied and characterized respectively, influencing the dissolvability of pigskin hide powder in ionic liquids aqueous two-phase system. It showed that salt in the aqueous two-phase system for K2HPO4 and for 62.5 mg/mL dissolved pigskin collagen when it was best. What' s more, when the dosage of pigskin hide powder was 11%, the solution had already saturated. FT1R spectra was used to observe the recycled ionic liquids and the regeneration of pigskin collagen. The recycled ionic liquid was well, and the , regeneration of pigskin collagen of the secondary structure of collagen didn' t changed.

  10. Purification of Active Myrosinase from Plants by Aqueous Two-Phase Counter-Current Chromatography

    Science.gov (United States)

    Wade, Kristina L.; Ito, Yoichiro; Ramarathnam, Aarthi; Holtzclaw, W. David; Fahey, Jed W.

    2014-01-01

    Introduction Myrosinase (thioglucoside glucohydrolase; E.C. 3.2.1.147), is a plant enzyme of increasing interest and importance to the biomedical community. Myrosinase catalyses the formation of isothiocyanates such as sulforaphane (frombroccoli) and 4-(α-l-rhamnopyranosyloxy)benzyl isothiocyanate (from moringa), which are potent inducers of the cytoprotective phase-2 response in humans, by hydrolysis of their abundant glucosinolate (β-thioglucoside N-hydroxysulphate) precursors. Objective To develop an aqueous two-phase counter-current chromatography (CCC) system for the rapid, three-step purification of catalytically active myrosinase. Methods A high-concentration potassium phosphate and polyethylene glycol biphasic aqueous two-phase system (ATPS) is used with a newly developed CCC configuration that utilises spiral-wound, flat-twisted tubing (with an ovoid cross-section). Results Making the initial crude plant extract directly in the ATPS and injecting only the lower phase permitted highly selective partitioning of the myrosinase complex before a short chromatography on a spiral disk CCC. Optimum phase retention and separation of myrosinase from other plant proteins afforded a 60-fold purification. Conclusion Catalytically active myrosinase is purified from 3-day broccoli sprouts, 7-day daikon sprouts, mustard seeds and the leaves of field-grown moringa trees, in a CCC system that is predictably scalable. PMID:25130502

  11. 苦瓜种子蛋白的双水相提取及抑菌性研究%Extraction of Seed Protein from Momordica charantia by Aqueous Two-phase System and Its Antibacterial Effect

    Institute of Scientific and Technical Information of China (English)

    于群; 朱新产

    2012-01-01

    Through screening and optimizing some influential factors, such as the mass fraction of polyethylene glycol (PEG) / ammonium sulfate aqueous two - phase, partition coefficient and recovery rate, the best conditions for the extraction of seed protein from balsam pear (Momordica charantia) were obtained. The result revealed that: when the mass fraction of ammonium sulfate and PEG was 26% and 22% respectively, the partition coefficient was the lowest (0.089), the recovery rate was the highest (96% ), and the purified seed protein with molecular weight 35.6 kD and 12.3 kD was acquired from Momordica charantia by aqueous two - phase system. The antibacterial tests indicated that Momordica charantia seed protein had various antibacterial effects to bacterium and fungus, and the antibacterial effect of the purified protein was better than that of the crude protein.%筛选优化了聚乙二醇(PEG)/硫酸铵双水相的质量分数、分配系数、回收率等影响因素,得到了苦瓜种子蛋白的最佳萃取条件:在26%硫酸铵、22%聚乙二醇条件下,分配系数最小,达0.089,回收率为96%,得到分子量为35.6 kD和12.3kD的苦瓜纯化蛋白.抑菌试验表明,苦瓜种子蛋白对细茵、真菌均有不同程度的抑制作用,且纯化蛋白的抑菌性大于粗提蛋白.

  12. Rationale for two phase polymer system microgravity separation experiments

    Science.gov (United States)

    Brooks, D. E.; Bamberger, S. B.; Harris, J. M.; Vanalstine, J.

    1984-01-01

    The two-phase systems that result when aqueous solutions of dextran and poly(ethylene glycol) are mixed at concentrations above a few percent are discussed. They provide useful media for the partition and isolation of macromolecules and cell subpopulations. By manipulating their composition, separations based on a variety of molecular and surface properties are achieved, including membrane hydrophobic properties, cell surface charge, and membrane antigenicity. Work on the mechanism of cell partition shows there is a randomizing, nonthermal energy present which reduces separation resolution. This stochastic energy is probably associated with hydrodynamic interactions present during separation. Because such factors should be markedly reduced in microgravity, a series of shuttle experiments to indicate approaches to increasing the resolution of the procedure are planned.

  13. An integrated practical implementation of continuous aqueous two-phase systems for the recovery of human IgG: From the microdevice to a multistage bench-scale mixer-settler device.

    Science.gov (United States)

    Espitia-Saloma, Edith; Vâzquez-Villegas, Patricia; Rito-Palomares, Marco; Aguilar, Oscar

    2016-05-01

    Aqueous two-phase systems (ATPS) are a liquid-liquid extraction technology with clear process benefits; however, its lack of industrial embracement is still a challenge to overcome. Antibodies are a potential product to be recovered by ATPS in a commercial context. The objective of this work is to present a more integral approach of the different isolated strategies that have arisen in order to enable a practical, generic implementation of ATPS, using human immunoglobulin G (IgG) as experimental model. A microfluidic device is used for ATPS parameters preselection for product recovery. ATPS were continuously operated in a mixer-settler device in one stage, multistage and multistage with recirculation configuration. Single-stage pure IgG extraction with a polyethylene glycol (PEG) 3350-phophates ATPS within continuous operation allowed a 65% recovery. Further implementation of a multistage platform promoted a higher particle partitioning reaching a 90% recovery. The processing of IgG from a cell supernatant culture harvest in a multistage system with top phase recirculation resulted in 78% IgG recovery in bottom phase. This work conjugates three not widely spread methodologies for ATPS: microfluidics, continuous and multistage operation. PMID:26848821

  14. A Novel Aqueous Two Phase System Composed of a Thermo-Separating Polymer and an Organic Solvent for Purification of Thermo-Acidic Amylase Enzyme from Red Pitaya (Hylocereus polyrhizus Peel

    Directory of Open Access Journals (Sweden)

    Mehrnoush Amid

    2014-05-01

    Full Text Available The purification of thermo-acidic amylase enzyme from red pitaya (Hylocereus polyrhizus peel for the first time was investigated using a novel aqueous two-phase system (ATPS consisting of a thermo-separating copolymer and an organic solvent. The effectiveness of different parameters such as molecular weight of the thermo-separating ethylene oxide-propylene oxide (EOPO copolymer and type and concentration of organic solvent on the partitioning behavior of amylase was investigated. In addition, the effects of phase components, volume ratio (VR, pH and crude load of purification factor and yield of amylase were evaluated to achieve the optimum partition conditions of the enzyme. In the novel ATPS method, the enzyme was satisfactorily partitioned into the polymer-rich top phase in the system composed of 30% (w/w EOPO 2500 and 15% (w/w 2-propanol, at a volume ratio of 1.94 and with a crude load scale of 25% (w/w at pH 5.0. Recovery and recycling of components was also measured in each successive step of the ATPS process. The enzyme was successfully recovered by the method with a high purification factor of 14.3 and yield of 96.6% and copolymer was also recovered and recycled at a rate above 97%, making the method was more economical than the traditional ATPS method.

  15. Partitioning behavior and structural characterization of papain in ionic liquid aqueous two-phase system%木瓜蛋白酶在离子液体双水相中的分配行为

    Institute of Scientific and Technical Information of China (English)

    王伟涛; 蒋志国; 张海德; 彭健; 许英豪; 董安华; 杨雪芳; 蒋欣欣

    2015-01-01

    Papain was extracted by ionic liquid aqueous two-phase system. Firstly,the influence of concentration, pH, and temperature of ionic liquid on the activity of papain was investigated. Secondly, the effects of different ionic liquid aqueous two-phase systems, alkyl chain lengths and concentrations of the ionic liquid, dosage of papain, pH, temperature on the partitioning behavior of papain were discussed. [C4mim]Cl and [C4mim]Br systems were better than [C4mim]BF4 system in extraction of papain, and it was disadvantageous to extract papain at a high temperature (60℃or higher). Activity recovery of enzyme reached 95.16%and purification factor reached 1.5 under the optimum conditions:[C4mim]Cl 0.25 g·ml−1, K2HPO4 0.35 g·ml−1, pH 8.0, enzyme addition 2.0 mg·ml−1, 30℃. The result laid the experimental basis for further scale-up research and commercial production.%采用离子液体双水相提取木瓜蛋白酶。首先考察不同浓度、pH、温度的离子液体对木瓜蛋白酶活性的影响,其次考察不同离子液体双水相体系、离子液体侧烷基链长度及浓度、酶添加量、pH、温度对木瓜蛋白酶分配行为的影响。结果表明:[C4mim]Cl 和[C4mim]Br 体系萃取木瓜蛋白酶的效果比[C4mim]BF4体系好;高温(≥60℃)对离子液体双水相体系萃取木瓜蛋白酶不利。离子液体双水相萃取木瓜蛋白酶的最佳工艺条件:0.25 g·ml−1的[C4mim]Cl,0.35 g·ml−1的K2HPO4,pH 8.0,酶添加量2.0 mg·ml−1,30℃。此条件下木瓜蛋白酶的酶活性回收率达到95.16%,纯化因子达到1.5。为今后进一步研究该体系的放大实验或规模化生产奠定了基础。

  16. Partial purification of glucose-6-phosphate dehydrogenase by aqueous two-phase poly(ethyleneglycol/phosphate systems Purificação parcial de glucose-6-fosfato desidrogenase por sistemas de duas fases aquosas poli (etilenoglicol/fosfato

    Directory of Open Access Journals (Sweden)

    Marcela Zanella Ribeiro

    2007-03-01

    Full Text Available Glucose-6-phosphate dehydrogenase (G6PDH is an important enzyme used in biochemical and medical studies and in several analytical methods that have industrial and commercial application. This work evaluated the extraction of G6PDH in aqueous two-phase system (ATPS of poly(ethyleneglycol (PEG/phosphate buffer, using as enzyme source a medium prepared through commercial baker's yeast disruption. Firstly, the effects of PEG molar mass on the enzyme partition and of homogenization and rest on the system equilibrium were investigated. Afterwards, several ATPS were prepared using statistical analysis (2² factorial design. The results, including kinetic and thermodynamic parameters for the G6PDH activity, showed partial purification of this enzyme in ATPS composed of 17.5% (w/w PEG400 and 15.0% (w/w phosphate. A high enzymatic recovery value (97.7%, a high partition coefficient (351, and an acceptable purification factor (2.28 times higher than in cell homogenate were attained from the top phase. So, it was possible to attain an effective enzyme pre-purification by separating some contaminants with a simple method such as liquid-liquid extraction in aqueous two-phase systems (ATPS.Glicose-6-fosfato desidrogenase (G6PDH é uma importante enzima usada em estudos bioquímicos e médicos, bem como em diversos métodos analíticos com aplicação comercial e industrial. Neste trabalho foi avaliado a extração da G6PDH em sistemas de duas fases aquosas (ATPS constituídos por poli(etilenoglicol (PEG/tampão fosfato, usando como fonte de enzima um meio preparado por rompimento de leveduras de panificação comercial. Inicialmente foram investigados os efeitos da massa molar do PEG na partição da enzima e da homogeneização e repouso no equilíbrio do sistema. Na sequência, diversos ATPS foram preparados usando análise estatística (planejamento fatorial 2². Os resultados, incluindo parâmetros cinéticos e termodinâmicos para a atividade da G6PDH

  17. Metallic and semiconducting carbon nanotubes separation using an aqueous two-phase separation technique: a review

    Science.gov (United States)

    Tang, Malcolm S. Y.; Ng, Eng-Poh; Juan, Joon Ching; Ooi, Chien Wei; Ling, Tau Chuan; Woon, Kai Lin; Loke Show, Pau

    2016-08-01

    It is known that carbon nanotubes show desirable physical and chemical properties with a wide array of potential applications. Nonetheless, their potential has been hampered by the difficulties in acquiring high purity, chiral-specific tubes. Considerable advancement has been made in terms of the purification of carbon nanotubes, for instance chemical oxidation, physical separation, and myriad combinations of physical and chemical methods. The aqueous two-phase separation technique has recently been demonstrated to be able to sort carbon nanotubes based on their chirality. The technique requires low cost polymers and salt, and is able to sort the tubes based on their diameter as well as metallicity. In this review, we aim to provide a review that could stimulate innovative thought on the progress of a carbon nanotubes sorting method using the aqueous two-phase separation method, and present possible future work and an outlook that could enhance the methodology.

  18. Scaling of Two-Phase Systems Across Gravity Levels Project

    Data.gov (United States)

    National Aeronautics and Space Administration — There is a defined need for long term earth based testing for the development and deployment of two-phase flow systems in reduced-gravity, including lunar gravity,...

  19. Application of aqueous two-phase systems for the development of a new method of cobalt(II), iron(III) and nickel(II) extraction: a green chemistry approach.

    Science.gov (United States)

    Patrício, Pamela da Rocha; Mesquita, Maiby Cabral; da Silva, Luis Henrique Mendes; da Silva, Maria C Hespanhol

    2011-10-15

    We have investigated the extraction behavior of the metallic ions Co(II), Fe(III) and Ni(II) as a function of the amount of potassium thiocyanate used as an extracting agent, using the following aqueous two-phase systems (ATPS): PEO + (NH(4))(2)SO(4) + H(2)O, PEO + Li(2)SO(4) + H(2)O, L35 + (NH(4))(2)SO(4) + H(2)O and L35 + (Li)(2)SO(4)+H(2)O. Metal extraction from the salt-rich phase to the polymer-rich phase is affected by the following parameters: amount of added extractant, pH, and the nature of the electrolyte and polymer that forms the ATPS. Maximal extraction percentages were obtained for Co(II) (99.8%), Fe(III) (12.7%) and Ni(II) (3.17%) when the ATPS was composed of PEO1500 + (NH(4))(2)SO(4) + H(2)O containing 1.4 mmol of KSCN at pH 4.0, providing separation factors as high as S(Co, Fe) = 3440 and S(Co, Ni) = 15,300. However, when the same ATPS was used at pH 2.0, the maximal extraction percentages for iron and nickel were 99.5% and 4.34%, respectively, with S(Fe, Ni) equal to 4380. The proposed technique was shown to be efficient in the extraction of Co(II) and Fe(III), with large viability for the selective separation of Co(II) and Fe(III) ions in the presence of Ni(II). PMID:21864977

  20. Application of aqueous two-phase systems for the development of a new method of cobalt(II), iron(III) and nickel(II) extraction: a green chemistry approach.

    Science.gov (United States)

    Patrício, Pamela da Rocha; Mesquita, Maiby Cabral; da Silva, Luis Henrique Mendes; da Silva, Maria C Hespanhol

    2011-10-15

    We have investigated the extraction behavior of the metallic ions Co(II), Fe(III) and Ni(II) as a function of the amount of potassium thiocyanate used as an extracting agent, using the following aqueous two-phase systems (ATPS): PEO + (NH(4))(2)SO(4) + H(2)O, PEO + Li(2)SO(4) + H(2)O, L35 + (NH(4))(2)SO(4) + H(2)O and L35 + (Li)(2)SO(4)+H(2)O. Metal extraction from the salt-rich phase to the polymer-rich phase is affected by the following parameters: amount of added extractant, pH, and the nature of the electrolyte and polymer that forms the ATPS. Maximal extraction percentages were obtained for Co(II) (99.8%), Fe(III) (12.7%) and Ni(II) (3.17%) when the ATPS was composed of PEO1500 + (NH(4))(2)SO(4) + H(2)O containing 1.4 mmol of KSCN at pH 4.0, providing separation factors as high as S(Co, Fe) = 3440 and S(Co, Ni) = 15,300. However, when the same ATPS was used at pH 2.0, the maximal extraction percentages for iron and nickel were 99.5% and 4.34%, respectively, with S(Fe, Ni) equal to 4380. The proposed technique was shown to be efficient in the extraction of Co(II) and Fe(III), with large viability for the selective separation of Co(II) and Fe(III) ions in the presence of Ni(II).

  1. Partitioning of Bovine Serum Albumin in Polyethylene Glycol(PEG)/Phosphate Aqueous Two-Phase System%PEG/磷酸盐双水相系统萃取BSA的研究

    Institute of Scientific and Technical Information of China (English)

    胡松青; 李琳; 李冰; 肖蕾

    2002-01-01

    BSA partitioning was performed in the PEG/phosphate aqueous two-phase system. The effects of the phase compositions concentrations, addition of NaCl and the initial concentration of BSA on the partition coefficient K and the fraction of BSA in the bottom phase Y were investigated. The results showed that BSA was enriched to the bottom phase. The phase compositions of PEG 6000 mass fraction is 10%/PO3-4 mass fraction is 6% and PEG 10000 mass fraction is 6%/PO3-4 mass fraction is 6% respectively were desirable for partitioning. The addition of NaCl showed no influence on BSA partitioning in PEG 6000 mass fraction is 10% /PO3-4 mass fraction is 6% system. The mathematical model for K was derived from the initial mass concentration of BSA and well fitting with the experimental data.%以PEG/磷酸盐双水相系统萃取BSA为对象,研究了双水相系统成相浓度、外加盐NaCl、BSA起始浓度等对BSA在两相间的分配系数和BSA下相萃取率的影响.结果发现,BSA大部分被萃取入双水相体系的下相,成相组成为PEG 6000 10% (质量分数)/ PO3-4 6% (质量分数)和PEG 10000 6% (质量分数)/ PO3-4 6% (质量分数)的双水相系统有利于BSA的萃取分配;外加NaCl对PEG 6000 10%(质量分数)/PO3-4 6%(质量分数)系统萃取BSA的影响不大;得出了上、下相BSA浓度和BSA在两相间分配系数K与系统BSA起始浓度之间的表达式,与实验结果有较好的拟合.

  2. 离子液体双水相萃取山楂黄酮和多糖的研究%Study on the Extraction of Hawthorn Flavonoids and Polysaccharide in Ionic Liquid Aqueous Two-Phase System

    Institute of Scientific and Technical Information of China (English)

    巩育军; 牛盛童; 黄学锋; 王键

    2014-01-01

    Partition behaviors of hawthorn flavonoids and polysaccharide in ionic liquid aqueous two-phase system(ILATPS)were studied by spectrophotometry.Effects of concentration of ionic liquid and ammonium sulfate,dosage of hawthorn and ultrasonic time on the extraction rate of hawthorn flavonoids and polysaccharide were investigated.The optimal extraction conditions were as follows:concentration of ionic liquid [Bmim]BF4 was 0.26~0.30 g·mL-1,concentration of ammonium sulfate was 0.08~0.10 g·mL-1,dosage of hawthorn was 0.14~0.17 g,ultrasonic time was 15~20 min.Under these conditions,extraction rate of hawthorn fla-vonoids was 86.4%~96.0% in the up phase,and extraction rate of polysaccharide was 75.2%~76.0% in the down phase.%采用分光光度法研究了山楂黄酮和多糖在[Bmim]BF4/(NH4)2 SO4双水相体系的分配行为,探讨了离子液体浓度、(NH4)2 SO4浓度、山楂用量和超声时间等因素对山楂黄酮和多糖萃取率的影响。确定最佳萃取条件为:离子液体[Bmim]BF4浓度0.26~0.30 g·mL-1,(NH4)2 SO4浓度0.08~0.10 g·mL-1,山楂用量0.14~0.17 g,超声时间15~20 min,在此优化条件下,双水相上相中黄酮的萃取率为86.4%~96.0%、下相中多糖的萃取率为75.2%~76.0%。

  3. 双水相萃取丽江山慈菇中的秋水仙碱%Extraction the Colchicine of Iphigenia indica in Aqueous Two-phase System

    Institute of Scientific and Technical Information of China (English)

    石瑶; 杨亚玲; 李晚谊; 刘谋盛

    2012-01-01

    建立了由聚乙二醇( PEG6000)与(NH4)2SO4形成的双水相体系萃取丽江山慈菇中秋水仙碱的新方法.考察了PEG分子量、PEG的浓度、(NH4)2SO4的浓度和pH值对双水相成相及秋水仙碱萃取率的影响,并结合HPLC对萃取相进行检测.结果表明:PEG6000质量分数为8%,(NH4)2SO4质量分数为20%,pH为7.0时,双水相体系对丽江山慈菇粗提液中秋水仙碱萃取率达82.09%,富集倍数为6.84倍.此方法可用于丽江山慈菇中秋水仙碱的初步分离富集,且操作简单,绿色无污染.%A new method to extract the colchicine of Iphigenia indica in aqueous two-phase system(ATPS) formed by macromolecular compound PEG6000 and (NH4 )2SO4 was investigated. The effect of the molecular weight of PEG, the concentration of PEG, the concentration of (NH4) 2SO4 and pH on phase behavior of the ATPS and extraction efficiencies of colchicines was investigated systematically. Determination the content of colchincine in the extraction phase combined with HPLC. The results showed that the best ATPS was composed of 8% PEG6000 and 20% (NH4)2SO4 ,pH 7.0. The extraction efficiency of colchicine of crude extract could reach to 82. 09% ,fold enrichment reach to 6. 84. This method could be used to initial separate and enrichment the colchicine of Iphigenia indica, simple operation and friendly to the environment.

  4. Extraction of spirulina platensis polysaccharide by ethanol/(NH4)2SO4 aqueous two-phase system%乙醇/硫酸铵双水相体系萃取螺旋藻多糖的研究

    Institute of Scientific and Technical Information of China (English)

    刘杨; 冯元琦; 陈美欣; 吴景淳; 黄海根

    2012-01-01

    Extraction of spirulina platensis polysaccharide by ethanol/( NH4 ) 2SO4 aqueous two-phase system(ATPS)was investigated. To remove and recycle the proteins, salting-out precipitation protein was carried out after spirulina platensis cells disruption. Spirulina platensis polysaccharide was extracted by traditional hot water diffusion and the polysaccharide dissolution rate reached 38.44 ± 1. 12mg/g spirulina platensis powder. Spirulina platensis polysaccharide was purified deeply by ethanol/ (NH4)2SO4 ATPS. The yield and enrichment factor of the polysaccharide were 84. 5±1. 45% and 6. 2 respectively,on the condition that the tie line length, volume ratio and pH of ATPS were 42. 9,1. 05 and 7. 0, respectively. The results indicated that spirulina platensis polysaccharide would be purified by a simple, efficient and low cost extraction technology using inexpensive ethanol/ (NH4)2SO4 ATPS.%考察了低分子有机溶剂与无机盐-乙醇/硫酸铵双水相体系萃取螺旋藻多糖的可行性及影响因素.研究结果表明:为除去并有效回收螺旋藻细胞中的蛋白质成分,在藻细胞破碎后进行盐析沉淀蛋白质,再采用传统的热水浸提法,可得到螺旋藻多糖的溶出率为38.44±1.12mg/g干燥粉;通过乙醇/硫酸铵双水相体系的萃取分配,在w(乙醇)=19%,w(硫酸铵)=27.5%(即双水相体系系线长度TLL =42.9),体系相比VR=1.05,pH=7.0时,螺旋藻多糖的收率可达84.5±1.45%,富集因子可达6.2.该研究结果表明廉价的乙醇/硫酸铵双水相萃取螺旋藻多糖将有望开发成为一条简洁、高效、低成本的螺旋藻多糖分离提取工艺.

  5. Controlling two-phase flow in microfluidic systems using electrowetting

    NARCIS (Netherlands)

    Gu, Hao

    2011-01-01

    Electrowetting (EW)-based digital microfluidic systems (DMF) and droplet-based two-phase flow microfluidic systems (TPF) with closed channels are the most widely used microfluidic platforms. In general, these two approaches have been considered independently. However, integrating the two technologie

  6. THERMAL PERFORMANCE OF A TWO PHASE CLOSED THERMOSYPHON USING AQUEOUS SOLUTION

    Directory of Open Access Journals (Sweden)

    M. Karthikeyan

    2010-05-01

    Full Text Available The thermal performance of an inclined two phase closed thermosyphon with different working fluid has been investigated experimentally in this paper. Distilled water and an aqueous solution that has a positive gradient of surface tension with temperature are used as the working fluid. A copper thermosyphon with a length of 1000 mm long, an inner diameter of 17 mm and an outer diameter of 19 mm was mployed. Each thermosyphon was charged with 60% of the working fluid and was tested with an evaporator length of 400 mm and condenser length of 450 mm. The thermosyphon was tested for various inclinations of 45○, 60○ and 90○ to the horizontal. Flow rate of 0.08Kg/min, 0.1 Kg/min and 0.12 Kg/min and heat input of 40 W, 60 W and 80 W were taken as input parameters. The thermal performance of aqueous solution charged two phase closed thermosyphon was out performed the distilled water in both heat transfer and temperature distribution.

  7. Ionic liquids for two-phase systems and their application for purification, extraction and biocatalysis.

    Science.gov (United States)

    Oppermann, Sebastian; Stein, Florian; Kragl, Udo

    2011-02-01

    The development of biotechnological processes using novel two-phase systems based on molten salts known as ionic liquids (ILs) got into the focus of interest. Many new approaches for the beneficial application of the interesting solvent have been published over the last years. ILs bring beneficial properties compared to organic solvents like nonflammability and nonvolatility. There are two possible ways to use the ILs: first, the hydrophobic ones as a substitute for organic solvents in pure two-phase systems with water and second, the hydrophilic ones in aqueous two-phase systems (ATPS). To effectively utilise IL-based two-phase systems or IL-based ATPS in biotechnology, extensive experimental work is required to gain the optimal system parameters to ensure selective extraction of the product of interest. This review will focus on the most actual findings dealing with the basic driving forces for the target extraction in IL-based ATPS as well as presenting some selected examples for the beneficial application of ILs as a substitute for organic solvents. Besides the research focusing on IL-based two-phase systems, the "green aspect" of ILs, due to their negligible vapour pressure, is widely discussed. We will present the newest results concerning ecotoxicity of ILs to get an overview of the state of the art concerning ILs and their utilisation in novel two-phase systems in biotechnology.

  8. Controlling two-phase flow in microfluidic systems using electrowetting

    OpenAIRE

    Gu, Hao

    2011-01-01

    Electrowetting (EW)-based digital microfluidic systems (DMF) and droplet-based two-phase flow microfluidic systems (TPF) with closed channels are the most widely used microfluidic platforms. In general, these two approaches have been considered independently. However, integrating the two technologies into one allows to combine the advantages of both worlds: (i) high throughput (from TPF) and (ii) precise control over each individual drop (from EW). Thus the aim of this thesis was to investiga...

  9. 双水相系统纯化山楂叶中黄酮类物质的研究%Research of Aqueous Two-phase Extraction System Purification Flavonoids of Hawthorn Leaves

    Institute of Scientific and Technical Information of China (English)

    赵立辉; 武文洁; 杨昱涵

    2009-01-01

    Aqueous two-phase extraction system (ATPE) which formed with water, alcohol and ammonium sulfate,is used to purify flavonoids substance and remove hydrophilic substance. This experiment identified the different influence factors of purification effect which included different salt,different volume rate of water and alcohol and addition of salt. Ammonium sulfate had the best parvafacies effect, and 2. 5 g ammonium sulfate just can satisfy the parvafacies. (1) In the ATPE of 5 mL alcohol + 5 mL distilled water + 5 g ammonium sulfate +0.15 g crude extraction( the content of crude extraction is 25% ) .recovery percent of flavonoids substance is 89.2% ,and the percent of flavonoids is 47. 6% in the purification product. (2)In the ATPE of 4 mL alcohol + 5 mL distilled water + 5 g ammonium sulfate +0.15 g crude extraction (the content of crude extraction is 25% ) , recovery percent of flavonoids substance is 81.9% , and the percent of flavonoids substance is 50.9% in the purification product. Literatures which purify the flavonoid substance of hawthorn leaves with ATPE including water, alcohol and ammonium sulfate, are seldom reported. This experiment using ATPE method can enhance the percent of flavonoid from 25% to 47.6% ,and the recovery percent is 89%.%应用水、乙醇和硫酸铵三者形成双水相系统,并利用黄酮在乙醇中的溶解度要大于水中的溶解度,以脱除其中一些易溶于水和在高浓度乙醇中溶解度低的物质.尝试了不同盐、不同体积比的乙醇和水、以及盐加入量对分相的影响并测定了其在不同情况下的纯化效果.发现在硫酸铵中的分相情况最好,在加入量到2.5 g时既可以达到分相完全.并测定:(1)在5 mL乙醇+5 mL水+5 g硫酸铵+0.15 g粗体物(粗体物中黄酮的百分含量为25%)的双水相中,黄酮类物质的回收率为89.2%,而黄酮百分含量提升为47.6%;(2)在4 mL乙醇+5mL水+5 g硫酸铵+0.15 g粗体物(粗体物中黄酮的百分含量为25%)的双

  10. Designing piping systems for two-phase flow

    International Nuclear Information System (INIS)

    A wide range of industrial systems, such as thermosiphon reboilers and chemical reactors, involve two-phase gas-liquid flow in conduits. Design of these systems requires information about the flow regime, pressure drop, slug velocity and length, and heat transfer coefficient. An understanding of two-phase flow is critical for the reliable and cost-effective design of such systems. The successful design of a pipeline in two-phase flow, for example, is a two-step process. The first step is the determination of the flow regime. If an undesirable flow regime, such as slug flow, is not anticipated and adequately designed for, the resulting flow pattern can upset a tower control system or cause mechanical failures of piping components. The second step is the calculation of flow parameters such as pressure drop and density to size lines and equipment. Since the mechanism of fluid flow (and heat transfer) depends on the flow pattern, separate flow models are required for different flow patterns

  11. Two-phase flow instability in a parallel multichannel system

    Institute of Scientific and Technical Information of China (English)

    HOU Suxia

    2009-01-01

    The two-phase flow instabilities observed in through parallel multichannel can be classified into three types, of which only one is intrinsic to parallel multichannel systems. The intrinsic instabilities observed in parallel multichannel system have been studied experimentally. The stable boundary of the flow in such a parallel-channel system are sought, and the nature of inlet flow oscillation in the unstable region has been examined experimentally under various conditions of inlet velocity, heat flux, liquid temperature, cross section of channel and entrance throttling. The results show that parallel multichannel system possess a characteristic oscillation that is quite independent of the magnitude and duration of the initial disturbance, and the stable boundary is influenced by the characteristic frequency of the system as well as by the exit quality when this is low, and upon raising the exit quality and reducing the characteristic frequency, the system increases its instability, and entrance throttling effectively contributes to stabilization of the system.

  12. Synthesis of 2-Phenylethanol by Bioconversion in Aqueous-Organic Solvent Two-phase System%水-聚丙二醇两相体系中生物转化法合成2-苯乙醇

    Institute of Scientific and Technical Information of China (English)

    陈虹; 陈蔚青; 张建芬

    2011-01-01

    研究了水-聚丙二醇两相体系中生物转化法合成2-苯乙醇的工艺条件,考察了聚丙二醇分子量、加量、转化振荡转速和底物浓度对2-苯乙醇合成的影响,确定了最佳的转化条件.结果表明,摇瓶中两相体系转化合成2-苯乙醇的最佳条件为:聚丙二醇分子量1500,加量为培养基体积的1/2,振荡转速250 r/min,底物浓度13g/L.在5L发酵罐中采用水-聚丙二醇两相体系生物转化法合成2-苯乙醇,浓度达6.87 g/L,产率为0.38 g/(L·h),较常规水相转化分别提高了42.2%和58.3%.%Production of 2-phenylethanol by byconversion was performed in a two-phase system composed of water and polypropylene glycol. The molecular weight and adding volume of polypropylene glycol, shaking speed for cultivation and concentration of L-phenylalanine were investigated to improve the productivity of 2-phenylethanol. The bioconversion process was carried out in a 5 L fermentor. The results indicated that the optimal conditions for 2-phenylethanol production in two-phase system were as follows: polypropylene glycol molecular weight was 1500, adding volume half of the volume of medium, shaking speed 250 r/min, and concentration of substrate 13 g/L. In the 5 L fermentor with polypropylene glycol by ISPR, the concentration and productivity of 2-phenylethanol were 6.87 g/L and 0.38 g/(Lh) respectively, compared with no polypropylene glycol extraction, which were improved by 42.2% and 58.3%.

  13. AQUEOUS TWO-PHASE GAS FLOATATION SPECTROPHOTOMETRIC DETERMINATION OF TRACE TETRACYCLINE IN ENVIRONMENTAL WATER SAMPLE

    Institute of Scientific and Technical Information of China (English)

    HOU Yanmin; YAN Yongsheng; LI Chunxiang; ZHAO Xiaojun; WANG Liang

    2008-01-01

    A green method for separating and enriching trace tetracycline (TC) in environment water by Aqueous Two-phase Gas Fioatation Spectrophotometry has been proposed, the principium was discussed.In this paper, the hydrophobic complex composed of Mg(Ⅱ) and TC was floated into organic phase under the optimal conditions: pH=10, the floatatlon equipment is home-made, n-propyl alcohol as the organic solvent, sodium chloride as the separating phase reagent.The data were obtained by spectrophotometry after floatatlon; The linear regression ,equation is A=2.33×105 C(mol/L)+0.2179, linear range is from 3.77×107mol/L to 6.32×105mol/L, respectively, with the correlation coefficient (r) better than 0.9997, relative recoveries is 99.7% to 100.3%, limit of detection was 4.29×10-8mol/L, The method can be applied to analyse the trace TC in water sample, the result is better.

  14. A TWO-PHASE APPROACH TO FUZZY SYSTEM IDENTIFICATION

    Institute of Scientific and Technical Information of China (English)

    Ta-Wei HUNG; Shu-Cherng FANG; Henry L.W.NUTTLE

    2003-01-01

    A two-phase approach to fuzzy system identification is proposed. The first phase produces a baseline design to identify a prototype fuzzy system for a target system from a coIlection of input-output data pairs. It uses two easily implemented clustering techniques: the subtractive clustering method and the fuzzy c-means (FCM) clustering algorithm. The second phase (fine tuning)is executed to adjust the parameters identified in the baseline design. This phase uses the steepest descent and recursive least-squares estimation methods. The proposed approach is validated by applying it to both a function approximation type of problem and a classification type of problem. An analysis of the learning behavior of the proposed approach for the two test problems is conducted for further confirmation.

  15. Extraction and isolation of lithospermic acid B from Salvia miltiorrhiza Bunge using aqueous two-phase extraction followed by high-performance liquid chromatography.

    Science.gov (United States)

    Guo, Yong Xue; Shi, Chang Zhi; Zhang, Lei; Lv, Lin; Zhang, Yue Yong

    2016-09-01

    A rapid and effective method integrating separation and purification of lithospermic acid B from Salvia miltiorrhiza Bunge was developed by combining an aqueous two-phase system extraction with preparative chromatography. An aqueous two-phase system of n-butyl alcohol/KH2 PO4 was chosen from seven systems. The influence of parameters including concentration of KH2 PO4 , n-butyl alcohol concentration, pH, and the ratio of an aqueous two-phase system to crude extract were investigated using a single factor design. Response surface methodology was subsequently used to find the optimal compositions of an aqueous two-phase system. Keeping a solvent-to-solid ratio of 10, the final optimized composition of an aqueous two-phase system was 39.1% w/w n-butyl alcohol and 22.6% w/w KH2 PO4 . Under these conditions a recovery yield of 99.8% and a high partition coefficient of 310.4 were obtained. In a pilot-scale experiment using optimized conditions, 18.79 g of lithospermic acid B with a purity of 70.5% and in a yield of 99.8% was separated from 0.5 kg of crude extract. Subsequently, 9.94 g lithospermic acid B with a purity of 99.3% and recovery yield of 70.3% was obtained with a preparative chromatographic process, and the two-step total recovery was 70.1%. PMID:27484287

  16. Effects of Hydrophobicity of Ethylene Oxide-Propylene Oxide Copolymers on Phase Diagrams of Aqueous Two-Phase Systems and Partition Behaviors of Cephalexin and 7-Aminodeacetoxicephalos Doranic Acid

    Institute of Scientific and Technical Information of China (English)

    朱建航; 魏东芝; 曹学君

    2002-01-01

    A series of ethylene oxide (EO)-propylene oxide (PO) random co-polymers (EOPO) were used to formaqueous two-phase systems (ATPS) with ammonium sulfate. Effects of EOPO's properties on the phase separationbehaviors and on the partition of cephalexin and 7-aminodesacetoxicephalosporanic acid (7-ADCA) in ATPS wereinvestigated. Both the molar mass and molar ratio of EO to PO of EOPO could greatly influence partition behaviorsof cephalexin and 7-ADCA as well as the binodal curve of ATPS. With the increase of molar mass of co-polymeror the decrease of molar ratio of EO to PO, the critical point of ATPS decreased, the binodal curve became moreasymmetry, and both cephalexin and 7-ADCA followed the same tendency to partition into the polymer-poorbottom phase. The experimental results shows that it is feasible to partition cephalexin and 7-ADCA in either thepolymer-rich top phase or the polymer-poor bottom phase by choosing a specific phase-forming EOPO.

  17. Lithium isotope separation factors of some two-phase equilibrium systems

    International Nuclear Information System (INIS)

    Isotope separation factors of seventeen two-phase equilibrium systems for lithium isotope enrichment have been determined. In all cases, lithium amalgam was used as one of the lithium-containing phases and was equilibrated with an aqueous or organic phase containing a lithium compound. In all systems examined, isotopic exchange was found to be extremely rapid, and 6Li was concentrated in the amalgam phase. The isotopic separation factor for the LiOH(aqueous) vs Li(amalgam) system has been studied as a function of temperature from -2 to 80 degreeC. The values obtained have been compared with the ''electrolysis'' and exchange separation factors given in the literature. The two-phase systems, LiCl(ethylenediamine) vs Li(amalgam) and LiCl(propylenediamine) vs Li(amalgam), have been studied, and the isotopic separation factors have been determined as functions of the temperature. The factors for the two systems have been found to be substantially the same (within limits of the errors involved) over the temperature range studied (0 to 100 degreeC) as those for the aqueous system. The isotopic separation factors for the seventeen systems have been tabulated, and correlations have been drawn that show the salt and solvent effects upon the values obtained

  18. Aqueous two-phase flotation for primary recovery of bacteriocin-like inhibitory substance (BLIS) from Pediococcus acidilactici Kp10.

    Science.gov (United States)

    Md Sidek, Nurul Lyana; Tan, Joo Shun; Abbasiliasi, Sahar; Wong, Fadzlie Wong Faizal; Mustafa, Shuhaimi; Ariff, Arbakariya B

    2016-08-01

    An aqueous two-phase flotation (ATPF) system based on polyethylene glycol (PEG) and sodium citrate (NaNO3C6H5O7·2H2O) was considered for primary recovery of bacteriocin-like inhibitory substance (BLIS) from Pediococcus acidilactici Kp10. The effects of ATPF parameters namely phase composition, tie-line length (TLL), volume ratio between the two phases (VR), amount of crude load (CL), pH, nitrogen gas flow rate (FR) and flotation time (FT) on the performance of recovery were evaluated. BLIS was mainly concentrated into the upper PEG-rich phase in all systems tested so far. The optimum conditions for BLIS purification, which composed of PEG 8000/sodium citrate, were: TLL of 42.6, VR of 0.4, CL of 22% (w/w), pH 7, average FT of 30min and FR of 20mL/min. BLIS was partially purified up to 5.9-fold with a separation efficiency of 99% under this optimal conditions. A maximum yield of BLIS activity of about 70.3% was recovered in the PEG phase. The BLIS from the top phase was successfully recovered with a single band in SDS-gel with molecular weight of about 10-15kDa. ATPF was found to be an effective technique for the recovery of BLIS from the fermentation broth of P. acidilactici Kp10. PMID:27262666

  19. Progress on the study of mechanism and partition behavior of papain in affinity aqueous two-phase systems%木瓜蛋白酶在亲和双水相系统中的分配行为及机制研究进展

    Institute of Scientific and Technical Information of China (English)

    张海德; 王伟涛; 蒋欣欣

    2013-01-01

    The separation methods of papain such as ultrafiltration, salt deposition, solvent extraction, affinity chromatography, aqueous two - phase extraction, affinity aqueous two-phase extraction and so on are evaluated. High purity papain can be expected to obtain by metal chelating affinity aqueous two-phase system (ATPS) technology, but the mechanism and partition behavior of papain in this system are not clear. It is important to study the interactions between papain and different metal ion affinity phase-separating agent, the adsorption kinetics model of papain in ATPS and the physical structure characterization and molecular simulation of the enzyme affinity adsorbent. Metal chelating affinity ATPS technology based on papain separation, will vigorously promote the development of papain industrialization and it has stimulative effect on the development of aqueous two-phase extraction technology.%  本文查阅相关文献,对木瓜蛋白酶传统提取方法(超滤法、盐析法、有机溶剂法、亲和层析法)及一些新兴的提取方法如双水相萃取法、亲和双水相法作了简要综述。利用金属螯合亲和双水相分配系统,能有效获得高纯度木瓜蛋白酶,但木瓜蛋白酶与亲和成相剂的相互作用及其分配行为与机制尚不清楚。研究木瓜蛋白酶与不同金属离子亲和成相剂之间的相互作用和吸附动力学模型;对酶的亲和结合物进行物理表征和分子模拟。阐明木瓜蛋白酶与不同金属离子亲和成相剂之间的亲和作用原理。将双水相萃取技术和亲和分配技术相融合,提出基于木瓜蛋白酶的金属螯合亲和双水相分配技术,该技术有望大力推动木瓜蛋白酶工业化高效制备的发展。

  20. 辛醇/水两相体系中生物合成L-苯基乙酰基甲醇的研究%Biotransformation of L-Phenylacetylcarbinol ( L-PAC ) Production in Aqueous/Octanol Two-Phase System

    Institute of Scientific and Technical Information of China (English)

    向禧; 尤晓清; 赵玉成; 赵刚刚; 邵飞; 卞筱泓; 许激扬

    2012-01-01

    利用酿酒酵母作为生物催化剂合成L-苯基乙酰基甲醇(L-Phenylacetylcarbiol,L-PAC)的过程中,通过加入有机溶剂(辛醇)形成两相体系,可改善底物和产物的溶解度,以减少对细胞内丙酮酸脱羧酶(PDC)的强烈抑制和钝化作用,从而促进L-PAC产量的提高.实验结果表明,两相体系合成L-PAC的最佳条件为活化60 min,苯甲醛的起始浓度940 mmol/L,丙酮酸钠的起始浓度460 mmol/L,葡萄糖的含量8%,水醇两相体积比为3:1,且加入一定量的甘油时,L-PAC产量可达在醇相中24.1 g/L和水相中3.7 g/L,比单一水相体系高出1.8倍.%L-Phenylacetylearbinol (L-PAC) ,a key pharmaceutical precursor for L-ephedrine synthesis,was produced from pyruvate and benzaldehyde using whole cells pyruvate decarboxylase ( PDC) from Saccharomyces cerevisiae in an aqueous/organic two-phase systems. In a solvent screen, octanol was identified as the most suitable solvent for PAC production in the two-phase systems. Using the systems have been evaluated for improved the solubility of substrate benzaldehyde and product PAC. The high partitioning coefficient of the toxicsubstrate benzaldehyde in octanol allowed delivery of large amounts of benzaldehyde into the aqueous phase. PDC catalyzed the biotransformation of benzaldehyde and pyruvate into PAC in the aqueous phase, and continuous extraction of PAC into the octanolphase further minimized enzyme inactivation and inhibition. It is clear that the results achieved with enhancing PAC production. For the two-phase system with a 3: 1 phase ratio,60minutes activation time,940 mmol/L benzaldehyde,460 mmol/L sodium pyruvate and 8% glucose,24. 1 g/L PAC was produced in the octanol phase and 3. 7 g/L in the aqueous phase with adding a certain amount of glycerol. By comparison with previously published data by our group utilizing whole cells of yeast for the traditional fermentation process aqueous single-phase system without octanol( 15 g/L PAC,200 mmol

  1. Degradation of chloramphenicol in aqueous solution using ozone oxidation in a two-phase system of water/loaded ozone organic solvent%水/载O3有机溶剂两相臭氧氧化法降解水体中氯霉素

    Institute of Scientific and Technical Information of China (English)

    李时银; 史震宇; 陆继来; 邹敏; 张利民

    2011-01-01

    Using a two-phase system of water/perfluorodecalin organic solvent loaded ozone, degradation of chloramphenicol in aqueous solution was conducted. Due to perfluorodecalin has a high ozone stability and solubility, chloramphenicol was used to examine the efficiency of the two-phase ozonation system. During the experiments, effects of initial pH and free radical scavenger on the removal rate of chloramphenicol were investigated respectively. The results showed that the efficiency of two-phase ozonation was increased with the increase of initial pH in water. It was also observed that free radical scavenger had no significant negative effect in two-phase ozonation.%以水/载O3有机溶剂(全氟萘烷)为新型两相臭氧氧化体系,研究了臭氧在全氟萘烷中的溶解度和稳定性,并考察了pH、NaHCO3和叔丁醇对两相体系中臭氧稳定性的影响;以水体中氯霉素为研究对象,考察了初始pH值和自由基抑制剂对两相臭氧氧化体系降解氯霉素效果的影响.结果表明:初始水相pH增大有利于氯霉素的降解;自由基抑制剂对两相体系氧化降解氯霉素影响不显著.

  2. Integrated downstream processing of lactoperoxidase from milk whey involving aqueous two-phase extraction and ultrasound-assisted ultrafiltration.

    Science.gov (United States)

    Nandini, K E; Rastogi, Navin K

    2011-01-01

    The present work involves the adoption of an integrated approach for the purification of lactoperoxidase from milk whey by coupling aqueous two-phase extraction (ATPE) with ultrasound-assisted ultrafiltration. The effect of system parameters of ATPE such as type of phase system, polyethylene glycol (PEG) molecular mass, system pH, tie line length and phase volume ratio was evaluated so as to obtain differential partitioning of contaminant proteins and lactoperoxidase in top and bottom phases, respectively. PEG 6000-potassium phosphate system was found to be suitable for the maximum activity recovery of lactoperoxidase 150.70% leading to 2.31-fold purity. Further, concentration and purification of enzyme was attempted using ultrafiltration. The activity recovery and purification factor achieved after ultrafiltration were 149.85% and 3.53-fold, respectively. To optimise productivity and cost-effectiveness of integrated process, influence of ultrasound for the enhancement of permeate flux during ultrafiltration was also investigated. Intermittent use of ultrasound along with stirring (2 min acoustic and 2 min stirring) resulted in increased permeate flux from 0.94 to 2.18 l/m(2) h in comparison to the ultrafiltration without ultrasound. The use of ultrasound during ultrafiltration resulted in increase in flux, but there was no significant change in activity recovery and purification factor. The integrated approach involving ATPE and ultrafiltration may prove to be a feasible method for the downstream processing of lactoperoxidase from milk whey.

  3. Single step aqueous two-phase extraction for downstream processing of C-phycocyanin from Spirulina platensis

    OpenAIRE

    Chethana, S.; Nayak, Chetan A.; M.C. Madhusudhan; Raghavarao, K. S. M. S.

    2014-01-01

    C-phycocyanin, a natural food colorant, is gaining importance worldwide due to its several medical and pharmaceutical applications. In the present study, aqueous two-phase extraction was shown to be an attractive alternative for the downstream processing of C-phycocyanin from Spirulina platensis. By employing differential partitioning, C-phycocyanin selectively partitioned to the polymer rich (top) phase in concentrated form and contaminant proteins to the salt rich (bottom) phase. This resul...

  4. A Simple Approach to Characterize Gas-Aqueous Liquid Two-phase Flow Configuration Based on Discrete Solid-Liquid Contact Electrification.

    Science.gov (United States)

    Choi, Dongwhi; Lee, Donghyeon; Kim, Dong Sung

    2015-10-14

    In this study, we first suggest a simple approach to characterize configuration of gas-aqueous liquid two-phase flow based on discrete solid-liquid contact electrification, which is a newly defined concept as a sequential process of solid-liquid contact and successive detachment of the contact liquid from the solid surface. This approach exhibits several advantages such as simple operation, precise measurement, and cost-effectiveness. By using electric potential that is spontaneously generated by discrete solid-liquid contact electrification, the configurations of the gas-aqueous liquid two-phase flow such as size of a gas slug and flow rate are precisely characterized. According to the experimental and numerical analyses on parameters that affect electric potential, gas slugs have been verified to behave similarly to point electric charges when the measuring point of the electric potential is far enough from the gas slug. In addition, the configuration of the gas-aqueous liquid two-phase microfluidic system with multiple gas slugs is also characterized by using the presented approach. For a proof-of-concept demonstration of using the proposed approach in a self-triggered sensor, a gas slug detector with a counter system is developed to show its practicality and applicability.

  5. Two phase instabilities system analysis with application on Clotaire experiments

    Energy Technology Data Exchange (ETDEWEB)

    Pascal Monier; Jacques Belleudy; Georges Brochier [PRINCIPIA R.D., Z.I. Athelia I, 13705 La Ciotat Cedex (France); Valerie Saldo; Jean-Marie Gouirand; Pierre Gubernatis [CEA Cadarache, 13108 St Paul Lez Durance, Cedex (France)

    2005-07-01

    Full text of publication follows: Natural-circulation cooled Boiling Water Reactors are susceptible to undergo thermal hydraulics instabilities. The so-called Type-II instabilities due to frictional pressure losses in the core may be observed typically at nominal pressure and relatively high power in BWRs. In the framework of the NACUSP (Natural Circulation and Stability Performance) Project, a test section simulating the riser at the exit of an ESBWR core (European Simplified Boiling Water Reactor) has been set up in the CLOTAIRE facility in CEA, Center of Cadarache. Test campaigns have been conducted with stationary tests demonstrating the correct scaling of the loop with R124a as coolant fluid and with unstable tests identifying the instability thresholds. The CEDRIC thermal hydraulics code was developed with TECHNICATOME in order to simulate one or two phase flow in compact on-board PWR used for marine propulsion. A generic version of this tool, CEDRIC MultiFluides has been used for modeling transient two phase flow until stability limit with large amplitude flow oscillations such as observed during the CLOTAIRE tests. This 1D unsteady model is based on a 3-equations model together with a phase velocities difference closure law in the frame of a Drift Flux Model. The main purpose of this paper is to present the experimental results of the CLOTAIRE tests together with the validation calculations. (authors)

  6. Effect of biochar addition on hydrogen and methane production in two-phase anaerobic digestion of aqueous carbohydrates food waste.

    Science.gov (United States)

    Sunyoto, Nimas M S; Zhu, Mingming; Zhang, Zhezi; Zhang, Dongke

    2016-11-01

    Effect of biochar addition on hydrogen and methane production in two-phase anaerobic digestion of aqueous carbohydrates was studied using bench-scale bioreactors. The cultures with biochar additions were placed in 100ml reactors and incubated at 35°C and pH 5 for hydrogen production. The residual cultures were then used for methane production, incubated at 35°C and pH 7. Daily yields of hydrogen and methane and weekly yield of volatile fatty acids (VFA) were measured. The hydrogen and methane production potentials, rate and lag phases of the two phases were analysed using the Gompertz model. The results showed that biochar addition increased the maximum production rates of hydrogen by 32.5% and methane 41.6%, improved hydrogen yield by 31.0% and methane 10.0%, and shortened the lag phases in the two phases by 36.0% and 41.0%, respectively. Biochar addition also enhanced VFA generation during hydrogen production and VFA degradation in methane production.

  7. Effect of biochar addition on hydrogen and methane production in two-phase anaerobic digestion of aqueous carbohydrates food waste.

    Science.gov (United States)

    Sunyoto, Nimas M S; Zhu, Mingming; Zhang, Zhezi; Zhang, Dongke

    2016-11-01

    Effect of biochar addition on hydrogen and methane production in two-phase anaerobic digestion of aqueous carbohydrates was studied using bench-scale bioreactors. The cultures with biochar additions were placed in 100ml reactors and incubated at 35°C and pH 5 for hydrogen production. The residual cultures were then used for methane production, incubated at 35°C and pH 7. Daily yields of hydrogen and methane and weekly yield of volatile fatty acids (VFA) were measured. The hydrogen and methane production potentials, rate and lag phases of the two phases were analysed using the Gompertz model. The results showed that biochar addition increased the maximum production rates of hydrogen by 32.5% and methane 41.6%, improved hydrogen yield by 31.0% and methane 10.0%, and shortened the lag phases in the two phases by 36.0% and 41.0%, respectively. Biochar addition also enhanced VFA generation during hydrogen production and VFA degradation in methane production. PMID:27474855

  8. Membrane-facilitated bioproduction of 3-methylcatechol in an octanol/water two-phase system.

    Science.gov (United States)

    Hüsken, Leonie E; Oomes, Mirjam; Schroën, Karin; Tramper, Johannes; de Bont, Jan A M; Beeftink, Rik

    2002-07-01

    Bioproduction of 3-methylcatechol from toluene by Pseudomonas putida MC2 was studied in the presence of an additional 1-octanol phase. This solvent was used to supply the substrate and extract the product, in order to keep the aqueous concentrations low. A hollow-fibre membrane kept the octanol and aqueous phase separated to prevent phase toxicity towards the bacterium. Volumetric production rates increased approximately 40% as compared to two-phase 3-methylcatechol production with direct phase contact. Preliminary investigations on downstream processing of 3-methylcatechol showed that 1 M of sodium hydroxide selectively extracted the disodium salt of 3-methylcatechol into an aqueous phase. PMID:12044556

  9. Effect of Soapberry Extraction on Lipase Activity of Fusarium sp.and Lipase Extraction by Aqueous Two-Phase Systems%无患子提取物对Fusarium sp.发酵产脂肪酶的影响及其双水相萃取分离

    Institute of Scientific and Technical Information of China (English)

    张海蓉; 蔡宇杰; 廖祥儒; 张峰; 张大兵

    2011-01-01

    Effect of surfactant on lipase production of Fusarium sp. Was investigated in this manuscript. The results showed that lipase activity was achieved at the maximum value in adding soapberry extraction, which indicated that soapberry extraction is the best surfactant, and lipase activity was the highest when the liquid-to-solid ratio is 6: l(mL : g). Lipase extraction by Aqueous Two-phase System following the precipitation of the crude enzymes by ammonium sulfate was also studied. The results indicated that the highest of decontamination factor F and extraction rate Sf achieved when the conditions of extraction showed as follows: the molecular weight of PEG was 4000, the concentration of PEG(M 4000)was 30 g/dL, and the concentration of NaH2 PO4 was 20 g/dL. At last, the lipase was purified 7. 92 folds and the recovery was 48. 30% by Aqueous Two-phase Systems.%研究了表面活性剂对Fusarium sp.的发酵产脂肪酶的影响.结果表明,添加无患子提取物的酶活为最高,说明无患子提取物是最佳的的表面活性剂,并且确定提取无患子提取物的液固比为6:1(mL∶g)时酶活达到最高.粗酶液经(NH4)2S04沉淀后进行双水相萃取分离,结果表明,采用质量浓度为30 g/dL的PEG(M 4000)和质量浓度为20 g/dL的NaH2 PO4时纯化系数F和萃取率Sf达到最高;经过双水相萃取后,该脂肪酶的纯化倍数可以达到7.92,回收率为48.30%.

  10. A two-phase system call arguments attribute analyzing method

    Institute of Scientific and Technical Information of China (English)

    LI Hong-jiao; LI Jian-hua

    2008-01-01

    To detect more attacks aiming at key security data in program behavior-based anomaly detection, the data flow properties were formulated as unary and binary relations on system call arguments. A new method named two-phrase analysis (2PA) is designed to analyze the efficient relation dependency, and its description as well as advantages are discussed. During the phase of static analysis, a dependency graph was constructed according to the program's data dependency graph, which was used in the phase of dynamic learning to learn specified binary relations. The constructed dependency graph only stores the information of related arguments and events, thus improves the efficiency of the learning algorithm and reduces the size of learned relation de-pendencies. Performance evaluations show that the new method is more efficient than existing methods.

  11. Enzymatic hydrolysis of penicillin in mixed ionic liquids/water two-phase system.

    Science.gov (United States)

    Jiang, Yangyang; Xia, Hansong; Guo, Chen; Mahmood, Iram; Liu, Huizhou

    2007-01-01

    In this paper, an integrated process involving the mixed ionic liquids/water two-phase system (MILWS) is proposed to improve the efficiency for enzymatic hydrolysis of penicillin G. First, hydrophilic [C4mim]BF4 (1-butyl-3-methylimidazolium tetrafluoraborate) and NaH2PO4 salt form an ionic liquids aqueous two-phase system (ILATPS), which could extract penicillin from its fermentation broth efficiently. Second, a hydrophobic [C4mim]PF6 (1-butyl-3-methylimidazolium hexafluoraphosphate) is introduced into the ionic liquids-rich phase of ILATPS containing penicillin and converses it into MILWS. Penicillin is hydrolyzed by penicillin acylase in the water phase of MILWS at pH 5. The byproduct phenylacetic acid (PAA) is partitioned into the ionic liquids mixture phase, while the intended product 6-aminopenicillanic acid (6-APA) is precipitated at this pH. In comparison with a similar butyl acetate/water system (BAWS) at pH 4, MILWS exhibits two advantages. (1) The selectivity between PAA and penicillin is greatly optimized at pH 5 by varying the mole ratio of [C4mim]PF6/[C4mim]BF4 in MILWS, whereas in BAWS the unalterable nature of the organic solvent restricts the optimized pH for maximum selectivity between PAA and penicillin at pH 4. (2) The pH for 6-APA precipitation in BAWS is 4, whereas it shifts to pH 5 in MILWS due to the complexation between negatively charged 6-APA and the cationic surface of the ionic liquids micelle. As a result, the removal of the two products from the enzyme sphere at relatively high pH is permitted in MILWS, which is beneficial for enzymatic activity and stability in comparison with the acidic pH 4 environment in BAWS.

  12. Symmetrical components and power analysis for a two-phase microgrid system

    DEFF Research Database (Denmark)

    Alibeik, M.; Santos Jr., E. C. dos; Blaabjerg, Frede

    2014-01-01

    This paper presents a mathematical model for the symmetrical components and power analysis of a new microgrid system consisting of three wires and two voltages in quadrature, which is designated as a two-phase microgrid. The two-phase microgrid presents the following advantages: 1) constant power...

  13. NaCl-丙醇双水相体系分离富集草甘膦生产废水中草甘膦铵盐%Separation and enrichment of glyphosate from glyphosate wastewater by NaCl/propanol aqueous two-phase system

    Institute of Scientific and Technical Information of China (English)

    余龙; 余凤; 陈俊

    2013-01-01

    By using aqueous two-phase system,which is formed by saturating NaCl that is in the glyphosate wastewater and propanol as a system to separate and enrich part of residues ammonium glyphosae in the glyphosate wastewater,the problems of resources recycling and recovery can be solved efficiently.The best extraction conditions can be determined by analyzing four factors:kinds and amounts of surfactant,pH,the amount of NaCl and propanol.The last step is to verify the scheme by simulation.The result indicates that the treatment of wastewater is ideal under this scheme which meets the requirements for industrialization and realizes 90.7% high recovery rate.%利用草甘膦生产废水中接近饱和的NaC1与丙醇形成的双水相体系分离富集废水中部分残留的草甘膦铵盐,达到了资源循环利用和资源的高效回收.通过分析表面活性剂种类及用量,pH,丙醇质量分数和NaC1质量分数4个因素确定了最佳萃取条件.最后对该方案进行仿真验证,表明利用该方案对实际废水的处理比较理想,实现了90.7%的高回收率,完全符合工业化要求.

  14. Distinguishing two-phase flow stability by using system identification method in a natural circulation system

    International Nuclear Information System (INIS)

    A research program on Two-phase flow stability in a natural circulation system has been executed in the Institute of Nuclear Energy Technology (INET), Tsinghua University in the development process of Nuclear Heating Reactor for the resent ten years. Two sets of experiment facility (HRTL-5 and HRTL-200) were erected, which serve as the simulator to the primary circuit of the nuclear heating reactor NHR-5 and NHR-200 separately, and were used for investigation on their thermo-physical behavior. Very important and useful results have been reached. The investigation presented, is one of the subject in the above mentioned research program. The main objective of the investigation is to develop a practical technology and method in engineering, based on general control theory, for distinguishing two-phase flow stability and identifying safety margin by using system identification method. By combining the two-phase flow stability theory in thermo-physics field with the system stability theory and system identification method in information science field, a thermo-hydraulic experiment technology with new concept was developed. The experiment was carried out on the thermohydraulic test system HRTL-5. Using reverse repeat pseudo-random sequences of heating power as the input signal sources and the measured flow rate as response function in the test, Two-phase flow stability and stability margin of the natural circulation system were investigated with analyzing the system pulse response function, Decay Ratio, and stability boundary under different operation conditions. The results are compared with that by using conventional method. The test system, test method and obtained typical results are provided

  15. Bioethanol production from corn stover using aqueous ammonia pretreatment and two-phase simultaneous saccharification and fermentation (TPSSF).

    Science.gov (United States)

    Li, Xuan; Kim, Tae Hyun; Nghiem, Nhuan P

    2010-08-01

    An integrated bioconversion process was developed to convert corn stover derived pentose and hexose to ethanol effectively. In this study, corn stover was pretreated by soaking in aqueous ammonia (SAA), which retained glucan ( approximately 100%) and xylan (>80%) in the solids. The pretreated carbohydrates-rich corn stover was converted to ethanol via two-phase simultaneous saccharification and fermentation (TPSSF). This single-reactor process employed sequential simultaneous saccharification and fermentation (SSF), i.e. pentose conversion using recombinant Escherichia coli KO11 in the first phase, followed by hexose conversion with Saccharomyces cerevisiae D5A in the second phase. In the first phase, 88% of xylan digestibility was achieved through the synergistic action of xylanase and endo-glucanase with minimal glucan hydrolysis (10.5%). Overall, the TPSSF using 12-h SAA-treated corn stover resulted in the highest ethanol concentration (22.3g/L), which was equivalent to 84% of the theoretical ethanol yield based on the total carbohydrates (glucan+xylan) in the untreated corn stover.

  16. Separation and determination of chloramphenicol in sewage using a small molecules-salt aqueous two-phase flotation system coupled with HPLC%小分子双水相浮选高效液相色谱法测定污水中痕量氯霉素

    Institute of Scientific and Technical Information of China (English)

    姚以亮; 关卫省

    2011-01-01

    用乙醇/磷酸氢二钾双水相体系浮选污水中的氯霉索,通过对盐的质量分数、有机溶剂的体积、气体流速和浮选时间的选择和优化,在理想条件下,氯霉素的平均浮选效率可以达到94%.该方法用于河水和鱼塘水样品中氯霉素的检测,检出限为0.5 ng/mL,加标回收率为89.44%~100.16%,相对标准偏差RSD为1.1%~2.1%,适用于污水中痕量氯霉素的分离/富集及分析测定.%C2H5OH/K2HPO4 two-phase aqueous system was used to floate CAP in sewage. By selecting and optimizing mass percentage of salt, volume of organic solvent, gas flow rate and flotation time, under the optimum conditions,the average floatation efficiency was up to 94% . The method used to detect CAP in the samples of river and pond water, the detection limit was 0. 5 ng/mL, the relative recovery was 89. 44% ~ 100. 16% with relative standard deviation RSD = 1. 1%~ 2. 1% . The method is applicable to analyze the trace CAP in swage.

  17. Development of high pressure two-phase choked flow analysis methodology in complex piping system

    International Nuclear Information System (INIS)

    Choked flow mechanism, characteristics of two-phase flow sound velocity and compressibility effects on flow through various piping system components are studied to develop analysis methodology for high pressure two-phase choked flow in complex piping system which allows choking flow rate evaluation and piping system design related analysis. Piping flow can be said choked if Mach number is equal to 1 and compressibility effects can be accounted through modified incompressible formula in momentum equation. Based on these findings, overall analysis system is developed to study thermal-hydraulic effects on steady-state piping system flow and future research items are presented. (Author)

  18. Design, Modelling and Simulation of Two-Phase Two-Stage Electronic System with Orthogonal Output for Supplying of Two-Phase ASM

    OpenAIRE

    Michal Prazenica; Branislav Dobrucky; Peter Sekerak; Lukas Kalamen

    2011-01-01

    This paper deals with the two-stage two-phase electronic systems with orthogonal output voltages and currents - DC/AC/AC. Design of two-stage DC/AC/AC high frequency converter with two-phase orthogonal output using single-phase matrix converter is also introduced. Output voltages of them are strongly nonharmonic ones, so they must be pulse-modulated due to requested nearly sinusoidal currents with low total harmonic distortion. Simulation experiment results of matrix converter for both steady...

  19. Enantioseparation of Racemic Flurbiprofen by Aqueous Two-Phase Extraction With Binary Chiral Selectors of L-dioctyl Tartrate and L-tryptophan.

    Science.gov (United States)

    Chen, Zhi; Zhang, Wei; Wang, Liping; Fan, Huajun; Wan, Qiang; Wu, Xuehao; Tang, Xunyou; Tang, James Z

    2015-09-01

    A novel method for chiral separation of flurbiprofen enantiomers was developed using aqueous two-phase extraction (ATPE) coupled with biphasic recognition chiral extraction (BRCE). An aqueous two-phase system (ATPS) was used as an extracting solvent which was composed of ethanol (35.0% w/w) and ammonium sulfate (18.0% w/w). The chiral selectors in ATPS for BRCE consideration were L-dioctyl tartrate and L-tryptophan, which were screened from amino acids, β-cyclodextrin derivatives, and L-tartrate esters. Factors such as the amounts of L-dioctyl tartrate and L-tryptophan, pH, flurbiprofen concentration, and the operation temperature were investigated in terms of chiral separation of flurbiprofen enantiomers. The optimum conditions were as follows: L-dioctyl tartrate, 80 mg; L-tryptophan, 40 mg; pH, 4.0; flurbiprofen concentration, 0.10 mmol/L; and temperature, 25 °C. The maximum separation factor α for flurbiprofen enantiomers could reach 2.34. The mechanism of chiral separation of flurbiprofen enantiomers is discussed and studied. The results showed that synergistic extraction has been established by L-dioctyl tartrate and L-tryptophan, which enantioselectively recognized R- and S-enantiomers in top and bottom phases, respectively. Compared to conventional liquid-liquid extraction, ATPE coupled with BRCE possessed higher separation efficiency and enantioselectivity without the use of any other organic solvents. The proposed method is a potential and powerful alternative to conventional extraction for separation of various enantiomers.

  20. Flow instabilities in two-phase flow system with and without phase change

    International Nuclear Information System (INIS)

    The gas-liquid two-phase flow of various types, such as single component or multiple components, and boiling two-phase flow or insulated two-phase flow, exist in piping systems, and the undesirable phenomena for the operation of systems such as the large scale pulsation of flow rate and the uneven distribution of flow may occur according to the condition. Generally these phenomena are called unstable flow. The author has carried out the research on unstable flow with air-water two-phase flow system, but a question arose to what extent the results in air-water system are applicable to boiling system. The unstable flow is explained with some examples. In this study, the similarity of pulsation in boiling system and insulated system was clarified, using the examples of pressure drop oscillation and flow rate distribution, and the theory to treat them in unified way was presented. The range of discussion is limited to the phenomena that do not depend on the microstructure of flow. The experimental setups were Freon boiling system, air-water capillary system and air-water vertical tube system. The characteristics of pressure drop oscillation and the fundamental mechanism, the theoretical analysis of pressure drop oscillation, the uneven distribution of flow rate in parallel tubes, the stability of flow rate distribution, and the numerical simulation are reported. (Kako, I.)

  1. Two-phase flow stability structure in a natural circulation system

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Zhiwei [Nuclear Engineering Laboratory Zurich (Switzerland)

    1995-09-01

    The present study reports a numerical analysis of two-phase flow stability structures in a natural circulation system with two parallel, heated channels. The numerical model is derived, based on the Galerkin moving nodal method. This analysis is related to some design options applicable to integral heating reactors with a slightly-boiling operation mode, and is also of general interest to similar facilities. The options include: (1) Symmetric heating and throttling; (2) Asymmetric heating and symmetric throttling; (3) Asymmetric heating and throttling. The oscillation modes for these variants are discussed. Comparisons with the data from the INET two-phase flow stability experiment have qualitatively validated the present analysis.

  2. Design, Modelling and Simulation of Two-Phase Two-Stage Electronic System with Orthogonal Output for Supplying of Two-Phase ASM

    Directory of Open Access Journals (Sweden)

    Lukas Kalamen

    2011-01-01

    Full Text Available This paper deals with the two-stage two-phase electronic systems with orthogonal output voltages and currents - DC/AC/AC. Design of two-stage DC/AC/AC high frequency converter with two-phase orthogonal output using single-phase matrix converter is also introduced. Output voltages of them are strongly nonharmonic ones, so they must be pulse-modulated due to requested nearly sinusoidal currents with low total harmonic distortion. Simulation experiment results of matrix converter for both steady and transient states for IM motors are given in the paper, also experimental verification under R-L load, so far. The simulation results confirm a very good time-waveform of the phase current and the system seems to be suitable for low-cost application in automotive/aerospace industries and application with high frequency voltage sources.

  3. Separation of gas from liquid in a two-phase flow system

    Science.gov (United States)

    Hayes, L. G.; Elliott, D. G.

    1973-01-01

    Separation system causes jets which leave two-phase nozzles to impinge on each other, so that liquid from jets tends to coalesce in center of combined jet streams while gas phase is forced to outer periphery. Thus, because liquid coalescence is achieved without resort to separation with solid surfaces, cycle efficiency is improved.

  4. RELAP5 two-phase fluid model and numerical scheme for economic LWR system simulation

    International Nuclear Information System (INIS)

    The RELAP5 two-phase fluid model and the associated numerical scheme are summarized. The experience accrued in development of a fast running light water reactor system transient analysis code is reviewed and example of the code application are given

  5. Study on the Ultrasound Extraction Coupling with Two-phase Aqueous System in the Extraction of Polyphenols from Mango Nuclear and Its Antioxidantion Activity%超声与双水相体系耦合提取芒果核多酚及活性研究

    Institute of Scientific and Technical Information of China (English)

    高云涛; 付艳丽; 李正全; 蒋进超

    2009-01-01

    利用超声与丙醇-硫酸铵双水相体系耦合对芒果核多酚进行提取分离,通过正交试验法对双水相形成和超声提取条件进行优化,最佳提取条件是:丙醇体积分数60%,超声提取15 min,(NH_4)_2SO_4用量为3 g/L,料液比(g∶mL)为1∶20,在此提取条件下多酚率提取率为6.96%,提取物中植物多酚纯度为37.8%,明显高于回流提取法.提取物对脂质过氧化及诱导红细胞氧化损伤具有良好的抑制作用,最大抑制率分别为66.8%和67.4%,方法简便、条件温和,环境友好.%The ultrasound extraction technology coupling with propyl-alcohol ammonium sulfate aqueous two-phase separation for extraction of polyphenols from mango nuclear was studied. The formation of aqueous two-phase and ultrasonic extraction conditions were optimized by orthogonal test,the optimum extraction conditions were; the propyl-alcohol solution (volume fraction as 60 % ),extraction time 15 min,0.30 ( NH_4)_2SO_4 0. 30 g/mL,the ratio of materials to solution as 1: 20 ( g/mL) . The extraction rates of polyphenols was 6. 96 % ( W/W),the purity of polyphenols was 37. 8 % (W/W) which was much higher than that of refluent ethanol extraction. The extractives singifi-cantly inhibit the lipid peroxidation (LPO) induced by ?OH free radical and hemoglobin ( RBC ) oxidate injury induced by free radical with the maximum inhibition rates of 66.8 % and 67.4 %,respectively. The proposed method is simply,mildly conditions and environmentally friend.

  6. Efeitos do pH e massa molar do polímero sobre o sistema bifásico aquoso PEG/fosfato = Effects of polymer pH and molar mass on the PEG/phosphate aqueous two-phase system

    Directory of Open Access Journals (Sweden)

    Elias Basile Tambourgi

    2011-07-01

    Full Text Available A extração líquido-líquido usando sistemas bifásicos aquosos (SBA é uma técnica promissora na purificação de biomoléculas de interesse industrial e laboratorial. Este trabalho tem por objetivo apresentar um estudo do diagrama de equilíbrio de fases para diferentes massas molares de polietileno glicol (PEG (400 e 4000 e fosfato de potássio a pHs que variam entre 6 e 11, em condições normais de temperatura e pressão. A influência do peso molecular do PEG em diferentes pHs foram estudados nos diagramas de fases formados. Foram preparadas concentrações de 100 e 50% (p p-1 para o PEG 400 e 4000,respectivamente. A 20% (p p-1 de KH2PO4/K2HPO4, a solução estoque do sal fosfato foi também preparada de forma a obter os pHs desejados (6, 7, 8 e 9. Para os pHs 10 e 11 além dos sais, foi utilizada uma solução de NaOH 1M. Os resultados mostraram que menores concentrações de soluções foram utilizadas para formar o SBA com o PEG de maior massa molar. Por outro lado, não houve influência do pH nas curvas de equilíbrio, ou seja, um deslocamento significativo da binodal em relação aos diferentes pHs.Liquid-liquid extraction using aqueous two-phase systems (ATPSs is a promising technique for the purification of biomolecules of industrial and laboratory interest. This work presents a study of the phase diagrams for different poly(ethylene glycol (PEG molar masses (ranging from 400 to 4000 and potassium phosphate at pH varying from 6 to 11 in standard conditions. The influence of PEG molecular mass at different pHs was studied from the phase diagrams formed. Stocksolutions of PEG 400 and 4000 (100 and 50% w w-1, respectively and phosphate (20% w w-1 KH2PO4/K2HPO4 were prepared at the appropriate pH (6, 7, 8 and 9. For pHs 10 and 11, NaOH 1M was used in addition to the salts. The results showed that low concentrations were used to form the ATPS with high molecular mass PEG. On the other hand, there was no pH influence in the

  7. Two-phase calculations and comparative flow experiments through heterogeneous orthogonal stratified systems

    Energy Technology Data Exchange (ETDEWEB)

    Laribi, S. (SONATRACH Centre de Recherche et Developpement, Boumerdes (Algeria)); Bertin, H.; Quintard, M. (Laboratoire ' Energetique et Phenomenes de Transfert' -ENSAM, URA CNRS 873, Talence (France))

    1995-01-01

    Experimental and theoretical results for two-phase flow in vertically stratified systems, the flow being normal to the strata, are presented. The experimental study is focused on the following points: (a) the initial oil-drainage process and the evolution of the water distribution during the capillary equilibrium process, and (b) the time evolution of the saturation fields during water-flooding experiments. Saturation fields were measured using a [gamma]-rays attenuation system. The physics of two-phase flow through vertically stratified porous media can be analysed by a large-scale averaging method. This methodology is described briefly; reference is made to previous publications for detailed presentation. The water-flooding experiments were interpreted using the large-scale averaging method, first in the quasi-static case, second using a simplified closure problem taking into account dynamic effects. The results show a better agreement between experimental and theoretical results when dynamic effects are taken into account

  8. The Influence of Morphology on the Charge Transport in Two-Phase Disordered Organic Systems

    OpenAIRE

    Woellner, Cristiano F.; Machado, Leonardo D.; Autreto, Pedro A.S.; Freire, Jose A.; Galvao, Douglas S.

    2015-01-01

    In this work we use a three-dimensional Pauli master equation to investigate the charge carrier mobility of a two-phase system, which can mimic donor-acceptor and amorphous- crystalline bulk heterojunctions. Our approach can be separated into two parts: the morphology generation and the charge transport modeling in the generated blend. The morphology part is based on a Monte Carlo simulation of binary mixtures (donor/acceptor). The second part is carried out by numerically solving the steady-...

  9. Extraction technology of pepsin from swine by PEG/(NH4)2SO4 aqueous two-phase system%聚乙二醇/硫酸铵双水相萃取猪胃蛋白酶工艺研究

    Institute of Scientific and Technical Information of China (English)

    张儒; 张变玲; 谢涛; 李谷才; 杨侃

    2012-01-01

    The pepsin was extracted and purified by PEG/(NH4)2SO4 aqueous two-phase system(ATPS)from stomach of swine.Extraction technology of pepsin using a newly established ATPS was investigated according to volume ratio(VR),purification factor(PF),specific activ%采用聚乙二醇/硫酸铵[PEG/(NH4)2SO4]建立稳定的双水相体系以分离猪胃蛋白酶。通过上下相体积比(VR)、比活力(SA)、纯化因子(PF)、酶活回收率(η)和SDS-聚丙烯酰胺凝胶电泳(SDS-PAGE)分析测定萃取效果。结果表明,萃取猪胃蛋白酶的最佳配比体系为25%PEG1000:18%(NH4)2SO4,所萃取的猪胃蛋白酶酶活回收率为91.5%,SDS-PAGE结果显示,萃取的蛋白质和猪胃蛋白酶对照品分子量大小一致。

  10. Two-phase distribution in the vertical flow line of a domestic wet central heating system

    Directory of Open Access Journals (Sweden)

    Ge Y.T.

    2013-04-01

    Full Text Available The theoretical and experimental aspects of bubble distribution in bubbly two-phase flow are reviewed in the context of the micro bubbles present in a domestic gas fired wet central heating system. The latter systems are mostly operated through the circulation of heated standard tap water through a closed loop circuit which often results in water supersaturated with dissolved air. This leads to micro bubble nucleation at the primary heat exchanger wall, followed by detachment along the flow. Consequently, a bubbly two-phase flow characterises the flow line of such systems. The two-phase distribution across the vertical and horizontal pipes was measured through a consideration of the volumetric void fraction, quantified through photographic techniques. The bubble distribution in the vertical pipe in down flow conditions was measured to be quasi homogenous across the pipe section with a negligible reduction in the void fraction at close proximity to the pipe wall. Such a reduction was more evident at lower bulk fluid velocities.

  11. Two-phase distribution in the vertical flow line of a domestic wet central heating system

    Science.gov (United States)

    Fsadni, A.-M.; Ge, Y. T.

    2013-04-01

    The theoretical and experimental aspects of bubble distribution in bubbly two-phase flow are reviewed in the context of the micro bubbles present in a domestic gas fired wet central heating system. The latter systems are mostly operated through the circulation of heated standard tap water through a closed loop circuit which often results in water supersaturated with dissolved air. This leads to micro bubble nucleation at the primary heat exchanger wall, followed by detachment along the flow. Consequently, a bubbly two-phase flow characterises the flow line of such systems. The two-phase distribution across the vertical and horizontal pipes was measured through a consideration of the volumetric void fraction, quantified through photographic techniques. The bubble distribution in the vertical pipe in down flow conditions was measured to be quasi homogenous across the pipe section with a negligible reduction in the void fraction at close proximity to the pipe wall. Such a reduction was more evident at lower bulk fluid velocities.

  12. A novel anaerobic two-phase system for biohydrogen production and in situ extraction of organic acid byproducts.

    Science.gov (United States)

    Sarma, Saurabh Jyoti; Brar, Satinder Kaur; Le Bihan, Yann; Buelna, Gerardo

    2015-06-01

    Owing to CO2-free emission, hydrogen is considered as a potential green alternative of fossil fuels. Water is the major emission of hydrogen combustion process and gravimetric energy density of hydrogen is nearly three times more than that of gasoline and diesel fuel. Biological hydrogen production, therefore, has commercial significance; especially, when it is produced from low-cost industrial waste-based feedstock. Light independent anaerobic fermentation is simple and mostly studied method of biohydrogen production. During hydrogen production by this method, a range of organic acid byproducts are produced. Accumulation of these byproducts is inhibitory for hydrogen production as it may result in process termination due to sharp decrease in medium pH or by possible metabolic shift. For the first time, therefore, a two-phase anaerobic bioreactor system has been reported for biohydrogen production which involves in situ extraction of different organic acids. Among different solvents, based on biocompatibility oleyl alcohol has been chosen as the organic phase of the two-phase system. An organic:aqueous phase ratio of 1:50 has been found to be optimum for hydrogen production. The strategy was capable of increasing the hydrogen production from 1.48 to 11.65 mmol/L-medium.

  13. First-Order System Least Squares and the Energetic Variational Approach for Two-Phase Flow

    CERN Document Server

    Adler, J H; Liu, C; Manteuffel, T; Zikatanov, L

    2010-01-01

    This paper develops a first-order system least-squares (FOSLS) formulation for equations of two-phase flow. The main goal is to show that this discretization, along with numerical techniques such as nested iteration, algebraic multigrid, and adaptive local refinement, can be used to solve these types of complex fluid flow problems. In addition, from an energetic variational approach, it can be shown that an important quantity to preserve in a given simulation is the energy law. We discuss the energy law and inherent structure for two-phase flow using the Allen-Cahn interface model and indicate how it is related to other complex fluid models, such as magnetohydrodynamics. Finally, we show that, using the FOSLS framework, one can still satisfy the appropriate energy law globally while using well-known numerical techniques.

  14. Economic analysis of uricase production under uncertainty: Contrast of chromatographic purification and aqueous two-phase extraction (with and without PEG recycle).

    Science.gov (United States)

    Torres-Acosta, Mario A; Aguilar-Yáñez, José M; Rito-Palomares, Marco; Titchener-Hooker, Nigel J

    2016-01-01

    Uricase is the enzyme responsible for the breakdown of uric acid, the key molecule leading to gout in humans, into allantoin, but it is absent in humans. It has been produced as a PEGylated pharmaceutical where the purification is performed through three sequential chromatographic columns. More recently an aqueous two-phase system (ATPS) was reported that could recover Uricase with high yield and purity. Although the use of ATPS can decrease cost and time, it also generates a large amount of waste. The ability, therefore, to recycle key components of ATPS is of interest. Economic modelling is a powerful tool that allows the bioprocess engineer to compare possible outcomes and find areas where further research or optimization might be required without recourse to extensive experiments and time. This research provides an economic analysis using the commercial software BioSolve of the strategies for Uricase production: chromatographic and ATPS, and includes a third bioprocess that uses material recycling. The key parameters that affect the process the most were located via a sensitivity analysis and evaluated with a Monte Carlo analysis. Results show that ATPS is far less expensive than chromatography, but that there is an area where the cost of production of both bioprocesses overlap. Furthermore, recycling does not impact the cost of production. This study serves to provide a framework for the economic analysis of Uricase production using alternative techniques.

  15. Two-Phase Cryogenic Heat Exchanger for the Thermodynamic Vent System

    Science.gov (United States)

    Christie, Robert J.

    2011-01-01

    A two-phase cryogenic heat exchanger for a thermodynamic vent system was designed and analyzed, and the predicted performance was compared with test results. A method for determining the required size of the Joule-Thomson device was also developed. Numerous sensitivity studies were performed to show that the design was robust and possessed a comfortable capacity margin. The comparison with the test results showed very similar heat extraction performance for similar inlet conditions. It was also shown that estimates for Joule- Thomson device flow rates and exit quality can vary significantly and these need to be accommodated for with a robust system design.

  16. Viscous singular shock profiles for a system of conservation laws modeling two-phase flow

    Science.gov (United States)

    Hsu, Ting-Hao

    2016-08-01

    This paper is concerned with singular shocks for a system of conservation laws via the Dafermos regularization ut + f(u)x = ɛtuxx. For a system modeling incompressible two-phase fluid flow, the existence of viscous profiles is proved using Geometric Singular Perturbation Theory. The weak convergence and the growth rate of the viscous solution are also derived; the weak limit is the sum of a piecewise constant function and a δ-measure supported on a shock line, and the maximum value of the viscous solution is of order exp ⁡ (1 / ɛ).

  17. 正交提取双水相体系纯化新楝果核印楝素的工艺研究%Study on separation of azadirachtin from new neem kernels by orthogonal design mode and aqueous two-phase system

    Institute of Scientific and Technical Information of China (English)

    王曼; 王佳静; 栾龙; 孙润广

    2014-01-01

    采用乙醇-无机盐双水相技术,研究了从国产新楝果核中提取印楝素的工艺.通过单因素实验和正交实验探讨了无机盐的质量浓度、提取时间、料液比对印楝素提取率的影响.实验结果表明:正交提取、双水相体系纯化印楝素的最佳条件是:无机盐浓度为0.62 g/mL,提取时间为1.5 h,料液比为1∶10(g∶mL),此时印楝素的提取率为1.23%.%The separation of azadirachtin from new neem kernels was studied by alcohol-inorganic salt a-queous two-phase extraction technology.The single factor and orthogonal experiments were done to in-vestigate the varitaion of azadirachtin extraction ratio relating to inorganic salt concentration,extraction time and material-solvent ratio.The results showed that the extraction rate of azadirachtin was 1 .2 3%under the optimum condition that the concentration of inorganic salt was 0.62 g/mL,the extraction time was 1 .5 h,and the material-solvent ratio was 1∶1 0 (g∶mL).

  18. Fractionation of aqueous sodium salts by liquid-liquid extraction in aqueous two phase systems

    NARCIS (Netherlands)

    Milosevic, M.; Staal, K.J.J.; Bargeman, G.; Schuur, B.; Haan, de A.B.

    2014-01-01

    An important element in the work-up of brines is the separation of different ions present. Usually, energy consuming technologies, such as multi-stage evaporation, reverse osmosis, crystallization, and nanofiltration, are used to bring the composition of the brine to the required specification. Frac

  19. A component architecture for the two-phase flows simulation system Neptune

    International Nuclear Information System (INIS)

    Electricite de France (EdF) and the French atomic energy commission (Cea) have planed a large project to build a new set of software in nuclear reactors analysis. One of the main idea is to allow coupled calculations in which several scientific domains are involved. This paper presents the software architecture of the two-phase flows simulation Neptune project. Neptune should allow computations of two-phase flows in 3 dimensions under normal operating conditions as well as safety conditions. Three scales are identified: the local scale where there is only homogenization between the two phases, an intermediate scale where solid internal structures are homogenized with the fluid and the system scale where some parts of the geometry under study are considered point-wise or subject to one dimensional simplifications. The main properties of this architecture are as follow: -) coupling with scientific domains, and between different scales, -) re-using of quite all or parts of existing validated codes, -) components usable by the different scales, -) easy introducing of new physical modeling as well as new numerical methods, -) local, distributed and parallel computing. The Neptune architecture is based on the component concept with stable and well suited interface. In the case of a distributed application the components are managed through a Corba bus. The building of the components is organized in shell: a programming shell (Fortran or C++ routines), a managing shell (C++ language), an interpreted shell (Python language), a Corba shell and a global driving shell (C++ or Python). Neptune will use the facilities offered by the Salome project: pre and post processors and controls. A data model has been built to have a common access to the information exchanged between the components (meshes, fields, physical and technical information). This architecture has first been setup and tested on some simple but significant cases and is now currently in use to build the Neptune

  20. Study of density wave phenomena in boiling and condensing two-phase flow systems

    International Nuclear Information System (INIS)

    In this work density wave oscillations are studied. This phenomenon have been widely studied for boiling systems with sub-cooled inlet condition in the past. The main purpose of this work is to characterize the stability region of boiling and condensing systems for sub-cooled and saturated inlet conditions. Stability maps, based on the sub-cooling and the phase-change numbers, are constructed. The limits of the unstable regions are identified and characterized. Finally some numerical simulations are presented in order to describe the nature of the involved phenomena. A high-order numerical solver, based on a homogenous two-phase model for a single boiling channel is implemented. (author)

  1. Silver nanoplates with ground or metastable structures obtained from template-free two-phase aqueous/organic synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Zhelev, Doncho V., E-mail: dontcho.jelev@nih.gov; Zheleva, Tsvetanka S. [Army Research Laboratory, 2800 Adelphi, Maryland 20783 (United States)

    2014-01-28

    Silver has unique electrical, catalytic, and plasmonic characteristics and has been widely sought for fabrication of nanostructures. The properties of silver nanostructures are intimately coupled to the structure of silver crystals. Two crystal structures are known for silver: the stable (ground) state cubic face centered 3C-Ag structure and the metastable hexagonal 4H-Ag structure. Recently, Chackraborty et al. [J. Phys.: Condens. Matter 23, 325401 (2011)] discovered a low density, highly reactive metastable hexagonal 2H-Ag structure accessible during electrodeposition of silver nanowires in porous anodic alumina templates. This 2H-Ag structure has enhanced electrical and catalytic characteristics. In the present work we report template-free synthesis of silver nanoplates with the metastable 2H-Ag crystal structure, which appears together with the ground 3C-Ag and the metastable 4H-Ag structures in a two-phase solution synthesis with citric acid as the capping agent. The capacity of citric acid to stabilize both the stable and the metastable structures is explained by its preferential binding to the close packed facets of Ag crystals, which are the (111) planes for 3C-Ag and the (0001) planes for 4H-Ag and 2H-Ag. Nanoplate morphology and structure are characterized using scanning electron microscopy, X-ray diffraction, and transmission electron microscopy. The synthesized nanoplates have thickness from 15 to 17 nm and edge length from 1 to 10 μm. Transmission electron microscopy selected area electron diffraction is used to uniquely identify and distinguish between nanoplates with 2H-Ag or 4H-Ag or 3C-Ag structures.

  2. Ionic liquid and aqueous two-phase extraction based on salting-out coupled with high-performance liquid chromatography for the determination of seven rare ginsenosides in Xue-Sai-Tong injection.

    Science.gov (United States)

    Li, Lan-Jie; Jin, Yong-Ri; Wang, Xiao-Zhong; Liu, Ying; Wu, Qian; Shi, Xiao-Lei; Li, Xu-Wen

    2015-09-01

    A method of ionic liquid salt aqueous two-phase extraction coupled with high-performance liquid chromatography has been developed for the analysis of seven rare ginsenosides including Rg6 , F4 , 20(S)-Rg3 , 20(R)-Rg3 , Rk3 , Rk1 , and Rg5 in Xue-Sai-Tong injection. The injection was mixed with ionic liquid 1-butyl-3-methylimidazolium bromide aqueous solution, and a mixture was obtained. With the addition of sodium dodecyl sulfate and dipotassium phosphate into the mixture, the aqueous two-phase mixture was formed after ultrasonic treatment and centrifuged. Rare ginsenosides were extracted into the upper phase. To obtain a high extraction factors, various influences were considered systematically, such as the volume of ionic liquid, the category and amount of salts, the amount of sodium dodecyl sulfate, the pH value of system, and the time of ultrasonic treatment. Under the optimal condition, rare ginsenosides in Xue-Sai-Tong injection were enriched and detected, the recoveries of seven rare ginsenosides ranged from 90.05 to 112.55%, while relative standard deviations were lower than 2.50%. The developed method was reliable, rapid and sensitive for the determination of seven rare ginsenosides in the injections.

  3. Two-phase equilibrium and molecular hydrogen formation in damped Lyman-alpha systems

    CERN Document Server

    Liszt, H S

    2002-01-01

    Molecular hydrogen is quite underabundant in damped Lyman-alpha systems at high redshift, when compared to the interstellar medium near the Sun. This has been interpreted as implying that the gas in damped Lyman-alpha systems is warm. like the nearby neutral intercloud medium, rather than cool, as in the clouds which give rise to most H I absorption in the Milky Way. Other lines of evidence suggest that the gas in damped Lyman-alpha systems -- in whole or part -- is actually cool; spectroscopy of neutral and ionized carbon, discussed here, shows that the damped Lyman-alpha systems observed at lower redshift z $$ 2.8 are warm (though not devoid of H2). To interpret the observations of carbon and hydrogen we constructed detailed numerical models of H2 formation under the conditions of two-phase thermal equilibrium, like those which account for conditions near the Sun, but with varying metallicity, dust-gas ratio, $etc$. We find that the low metallicity of damped Lyman-alpha systems is enough to suppress H2 form...

  4. An analytical method for modeling two-phase gravity-driven drainage systems in BOP applications

    International Nuclear Information System (INIS)

    Highlights: ► An actual gravity drainage system in an operating power plant is described. ► A drain flow oscillation exists in the system, which is replicated using RELAP5. ► The RELAP model identifies that steam binding due to poor venting is the cause. ► The RELAP model shows that new vent piping prevents the flow oscillations. ► The revised vent piping is installed in the plant and resolves the flow oscillations. - Abstract: Two-phase gravity-driven drainage systems are used in many applications within nuclear power Balance of Plant (BOP) applications such as the drain lines for moisture separator re-heaters (MSRs) and feedwater heaters. Design of these systems is typically based on industry-oriented guidelines and operator-based experience. Changes in plant operation, such as uprates and equipment modification and/or replacement, are relatively common as plants seek to generate more power with greater efficiency. These plant modifications may inadvertently change system operation from design conditions and impose undesirable system transients. This paper seeks to provide a method for analyzing BOP drainage systems in an effort to characterize and mitigate drain flow transients. Previous methodologies diagnose and evaluate drain instability through measurement, empirical analysis, and operational experience. This paper identifies methods that can be utilized to generate computational models of discrete plant drainage systems that decrease the level of speculation involved in previous analyses. Additionally, a real-world application of this method is presented to demonstrate how computer modeling can accurately mimic plant transients.

  5. Development of an Enhanced Two-Phase Production System at the Geysers Geothermal Field; FINAL

    International Nuclear Information System (INIS)

    A method was developed to enhance geothermal steam production from two-phase wells at THE Geysers Geothermal Field. The beneficial result was increased geothermal production that was easily and economically delivered to the power plant

  6. Multinuclear NMR microscopy of two-phase fluid systems in porous rock.

    Science.gov (United States)

    Doughty, D A; Tomutsa, L

    1996-01-01

    The high-field magnetic resonance (MR) characteristics of fluids in porous reservoir rock exhibit short T2 relaxation times and broad natural line widths. These characteristics severely restrict which MR imaging (MRI) methodology can be used to obtain high-resolution porescale images of fluids in porous rock. An MR microscopy protocol based on 3D backprojection using strong imaging gradients was developed to overcome many of these constraints. To improve the image quality of two-phase systems, multinuclear MRI using proton MR to image the brine phase and 19F MR of a fluorinated hydrocarbon to image the oil phase was used. Resolution as high as 25 microns per pixel has been obtained for fluid systems in Bentheim and Fontainebleau sandstones. Separate proton and 19F images of brine and oil phases show good agreement with total saturation images. Software has been developed to perform 3D erosion/dilations and to extract the pore size distribution from binarized 3D images of fluid filled porosity. Results from pore size measurements show significant differences in the nature of the pore network in Fontainebleau and Bentheim sandstones. PMID:8970097

  7. Hydrodynamic Dryout in Two-Phase Flows: Observations of Low Bond Number Systems

    Science.gov (United States)

    Weislogel, Mark M.; McQuillen, John B.

    1998-01-01

    Dryout occurs readily in certain slug and annular two-phase flows for systems that exhibit partial wetting. The mechanism for the ultimate rupture of the film is attributed to van der Waals forces, but the pace towards rupture is quickened by the surface tension instability (Rayleigh-type) of the annular film left by the advancing slug and by the many perturbations of the free surface present in the Re(sub g) approximately 0(10(exp 3)), Re(sub l) approximately 0(10(exp 4)), and Ca approximately 0(10(exp -1) flows. Results from low-gravity experiments using three different test fluids are presented and discussed. For the range of tests conducted, the effect of increasing viscosity is shown to eliminate the film rupture while the decrease of surface tension via a surfactant additive is shown to dramatically enhance it. Laboratory measurements using capillary tubes are presented which reveal the sensitivity of the dryout phenomena to particulate and surfactant contamination. Rom such observations, dryout due to the hydrodynamic-van der Waals instability can be expected in a certain range of flow parameters in the absence of heat transfer. The addition of heat transfer may only exacerbate the problem by producing thermal transport lines replete with "hot spots." A caution to this effect is issued to future space systems designers concerning the use of partially wetting working fluids.

  8. Effective thermal conductivity of real two-phase systems using resistor model with ellipsoidal inclusions

    Indian Academy of Sciences (India)

    Jagjiwanram; Ramvir Singh

    2004-08-01

    A theoretical model has been developed for real two-phase system assuming linear flow of heat flux lines having ellipsoidal particles arranged in a three-dimensional cubic array. The arrangement has been divided into unit cells, each of which contains an ellipsoid. The resistor model has been applied to determine the effective thermal conductivity (ETC) of the unit cell. To take account of random packing of the phases, non-uniform shape of the particles and non-linear flow of heat flux lines in real systems, incorporating an empirical correction factor in place of physical porosity modifies an expression for ETC. An effort is made to correlate it in terms of the ratio of thermal conductivities of the constituents and the physical porosity. Theoretical expression so obtained has been tested on a large number of samples cited in the literature and found that the values predicted are quite close to the experimental results. Comparison of our model with different models cited in the literature has also been made.

  9. Thermocapillary Levitation of Nanoliter-Volume Droplets and Extension to Two-Phase Systems

    Science.gov (United States)

    Black, James; Neitzel, G. Paul

    2012-11-01

    The development of a novel method of droplet levitation to be employed in lab-on-a-chip (LOC) applications relies upon the mechanism of thermocapillary convection (due to the temperature dependence of surface tension) to drive a layer of lubricating gas between droplet and substrate. The fact that most droplets of interest in LOC applications are aqueous in nature, coupled with the fact that success in effecting thermocapillary transport in aqueous solutions has been limited, has led to the development of a technique for the controlled encapsulation of nanoliter-volume water droplets within a shell of inert silicone oil. Previously, microliter-volume single-phase silicone-oil droplets have been levitated. This work aims to extend this technique to nanoliter-volume single- and compound-phase oil and water droplets as well as ascertain how the fluid-fluid interface affects the internal convective currents driven by the surface flow in compound-phase systems. Supported by NASA and NSF.

  10. Controlling the long-range corrections in atomistic Monte Carlo simulations of two-phase systems.

    Science.gov (United States)

    Goujon, Florent; Ghoufi, Aziz; Malfreyt, Patrice; Tildesley, Dominic J

    2015-10-13

    The long-range correction to the surface tension can amount to up to 55% of the calculated value of the surface tension for cutoffs in the range of 2.1-6.4 σ. The calculation of the long-range corrections to the surface tension and to the configurational energy in two-phase systems remains an active area of research. In this work, we compare the long-range corrections methods proposed by Guo and Lu ( J. Chem. Phys. 1997 , 106 , 3688 - 3695 ) and Janeček ( J. Phys. Chem. B 2006 , 110 , 6264 - 6269 ) for the calculation of the surface tension and of the coexisting densities in Monte Carlo simulations of the truncated Lennard-Jones potential and the truncated and shifted Lennard-Jones potential models. These methods require an estimate of the long-range correction at each step in the Monte Carlo simulation. We apply the full version of the Guo and Lu method, which involves the calculation of a double integral that contains a series of density differences, and we compare these results with the simplified version of the method which is routinely used in two-phase simulations. We conclude that the cutoff dependencies of the surface tension and coexisting densities are identical for the full versions of Guo and Lu and Janeček methods. We show that it is possible to avoid applying the long-range correction at every step by using the truncated Lennard-Jones potential with a cutoff rc ≥ 5 σ. The long-range correction can then be applied at the end of the simulation. The limiting factor in the accurate calculation of this final correction is an accurate estimate of the coexisting densities. Link-cell simulations performed using a cutoff rc = 5.5 σ require twice as much computing time as those with a more typical cutoff of rc = 3.0 σ. The application of the Janeček correction increases the running time of the simulation by less than 10%, and it can be profitably applied with the shorter cutoff. PMID:26574249

  11. Rheology of two-phase systems: A microphysical and observational approach

    Science.gov (United States)

    Platt, John P.

    2015-08-01

    Ductile shear zones commonly contain distinctive bands of high strain rock characterized by intimately mixed fine-grained two-phase or polyphase material. These ultramylonite bands are weaker than the surrounding material, and may play a critical role in strain localization. How such zones develop, how the phases become evenly dispersed, the bulk rheology, and the controls on grain size, are all unclear. The following generic scenario may resolve some of these questions. 1) Dislocation creep and dynamic recrystallization cause grain-size reduction: commonly, the recrystallized grain sizes of the two phases differ. 2) Grain size reduction causes a switch to grain-boundary diffusion creep, which requires grain-boundary sliding. Diffusion allows one phase to fill spaces that open between grains of the other: this will happen most rapidly in the finer-grained phase. The grain size of the resulting mixture is therefore controlled by that of the finer-grained phase. This leads to mixing and dispersion of the two phases, producing a fine-grained, evenly dispersed two-phase aggregate. 3) The bulk rheology will be controlled by grain-boundary diffusion creep of the two phases, with the grain size controlled by the finer-grained phase. Bulk flow laws can be developed for quartz-feldspar and olivine-orthopyroxene ultramylonites based on these concepts, using appropriate mixing laws.

  12. Release of lonapalene from two-phase emulsion-type ointment systems.

    Science.gov (United States)

    Ong, J T; Manoukian, E

    1988-01-01

    The in vitro release of lonapalene, a novel nonsteroidal antipsoriatic agent, was studied from two-phase emulsion-type ointment systems into a perfect sink of propylene carbonate at 32 degrees C. Lonapalene was completely solubilized in the ointments consisting of an internal phase of propylene carbonate (PC)-propylene glycol (PG) mixture dispersed within an external phase of a petrolatum base. The PC:PG ratio was varied to investigate separately the effects of (1) the initial concentration of lonapalene, (2) its saturation level, and (3) the volume fraction of the internal phase. The release profile consisted of an initial release rate which was higher than the ensuing diffusion-controlled release rate. The initial rate was attributed to the release of lonapalene from the surface globules of internal phase directly into the sink. Both rates increased with increasing lonapalene initial concentration in the ointment. For ointment systems in which the saturation level of lonapalene was kept constant, neither release rate was affected by the increasing volume fraction of the internal phase up to 12%. Further increase in this volume fraction to 25% afforded a significantly higher initial rate, while the diffusion-controlled rate was unchanged. However, an increase in the volume fraction of the internal phase with a concomitant decrease in the saturation level of lonapalene in the ointment resulted in a decrease in the initial rates and, to a lesser degree, the diffusion-controlled release rates. The diffusion coefficient in the external phase, calculated from the effective diffusion coefficient, was (2.68 +/- 0.24) X 10(-9) cm2/sec. PMID:3244603

  13. Numerical modeling of two-phase flow in the sodium chloride-water system with applications to seafloor hydrothermal systems

    Science.gov (United States)

    Lewis, Kayla C.

    In order to explain the observed time-dependent salinity variations in seafloor hydrothermal vent fluids, quasi-numerical and fully numerical fluid flow models of the NaCl-H2O system are constructed. For the quasi-numerical model, a simplified treatment of phase separation of seawater near an igneous dike is employed to obtain rough estimates of the thickness and duration of the two-phase zone, the amount of brine formed, and its distribution in the subsurface. Under the assumption that heat transfer occurs mainly by thermal conduction it is shown that, for a two-meter wide dike, the maximum width of the two phase zone is approximately 20 cm and that a zone of halite is deposited near the dike wall. The two-phase zone is mainly filled with vapor. After 13 days, the two-phase zone begins to disappear at the base of the system, and disappears completely by 16 days. The results of this simplified model agree reasonably well with transient numerical solutions for the analogous two-phase flow in a pure water system. The seafloor values of vapor salinity given by the model are compared with vapor salinity data from the "A" vent at 9-10°N on the East Pacific Rise and it is argued that either non-equilibrium thermodynamic behavior or near-surface mixing of brine with vapor in the two-phase region may explain the discrepancies between model predictions and data. For the fully numerical model, the equations governing fluid flow, the thermodynamic relations between various quantities employed, and the coupling of these elements together in a time marching scheme is discussed. The thermodynamic relations are expressed in terms of equations of state, and the latter are shown to vary both smoothly and physically in P-T-X space. In particular, vapor salinity values near the vapor-liquid-halite coexistence surface are shown to be in strong agreement with recently measured values. The fully numerical model is benchmarked against previously published heat pipe and Elder problem

  14. Scaling of the steady state and stability behaviour of single and two-phase natural circulation systems

    International Nuclear Information System (INIS)

    Scaling methods for both single-phase and two-phase natural circulation systems have been presented. For single-phase systems, simulation of the steady state flow can be achieved by preserving just one nondimensional parameter. For uniform diameter two-phase systems also, it is possible to simulate the steady state behaviour with just one non-dimensional parameter. Simulation of the stability behaviour requires geometric similarity in addition to the similarity of the physical parameters appearing in the governing equations. The scaling laws proposed have been tested with experimental data in case of single-phase natural circulation. (author)

  15. Releasing intracellular product to prepare whole cell biocatalyst for biosynthesis of Monascus pigments in water-edible oil two-phase system.

    Science.gov (United States)

    Hu, Minglue; Zhang, Xuehong; Wang, Zhilong

    2016-11-01

    Selective releasing intracellular product in Triton X-100 micelle aqueous solution to prepare whole cell biocatalyst is a novel strategy for biosynthesis of Monascus pigments, in which cell suspension culture exhibits some advantages comparing with the corresponding growing cell submerged culture. In the present work, the nonionic surfactant Triton X-100 was successfully replaced by edible plant oils for releasing intracellular Monascus pigments. High concentration of Monascus pigments (with absorbance nearly 710 AU at 470 nm in the oil phase, normalized to the aqueous phase volume approximately 142 AU) was achieved by cell suspension culture in peanut oil-water two-phase system. Furthermore, the utilization of edible oil as extractant also fulfills the demand for application of Monascus pigments as natural food colorant.

  16. Cloning of Toluene 4-Monooxygenase Genes and Application of Two-Phase System to the Production of the Anticancer Agent, Indirubin.

    Science.gov (United States)

    Wongsaroj, Lampet; Sallabhan, Ratiboot; Dubbs, James M; Mongkolsuk, Skorn; Loprasert, Suvit

    2015-08-01

    Indirubin is a strong inhibitor of several eukaryotic cell signaling pathways and shows promise as a treatment for myelocytic leukemia and Alzheimer's disease. The tmoABCDEF operon, encoding the components of a novel toluene 4-monooxygenase from the paint factory soil isolate, Pseudomonas sp. M4, was cloned and expressed in Escherichia coli. E. coli::pKSR12 expressing the tmo genes was used to develop a two-phase [dioctyl phthalate (DOP)/aqueous medium] culture system that was optimized to obtain maximal yields of indirubin from the starting substrate, indole. DOP was used as the organic phase to solubilize and sequester the toxic indole substrate, making possible the use of high indole concentrations that would otherwise interfere with growth in aqueous media. A 50 % (v/v) DOP two-phase system using tryptophan medium containing 3 mM cysteine, 5 mM indole, and 1 mM isatin yielded 102.4 mg/L of indirubin with no conversion of indole to the less valuable alternate product, indigo. PMID:25779640

  17. A numerical method for a model of two-phase flow in a coupled free flow and porous media system

    KAUST Repository

    Chen, Jie

    2014-07-01

    In this article, we study two-phase fluid flow in coupled free flow and porous media regions. The model consists of coupled Cahn-Hilliard and Navier-Stokes equations in the free fluid region and the two-phase Darcy law in the porous medium region. We propose a Robin-Robin domain decomposition method for the coupled Navier-Stokes and Darcy system with the generalized Beavers-Joseph-Saffman condition on the interface between the free flow and the porous media regions. Numerical examples are presented to illustrate the effectiveness of this method. © 2014 Elsevier Inc.

  18. Two-phase plate-fin heat exchanger modeling for waste heat recovery systems in diesel engines

    NARCIS (Netherlands)

    Feru, E.; de Jager, B.; Willems, F.; Steinbuch, M.

    2014-01-01

    This paper presents the modeling and model validation for a modular two-phase heat exchanger that recovers energy in heavy-duty diesel engines. The model is developed for temperature and vapor quality prediction and for control design of the waste heat recovery system. In the studied waste heat reco

  19. Study of nonionic surfactant aqueous two-phase extraction of amino acids%非离子表面活性剂双水相萃取氨基酸研究

    Institute of Scientific and Technical Information of China (English)

    孙晨; 刘广宇; 徐培辉

    2014-01-01

    This paper mainly researches on the phase behavior of the extraction distribution amino acid extract in nonionic surfactant in aqueous two-phase system. Extraction of L-phenylalanine with AEO-7/Na3PO4 aqueous two-phase,the effects of the content of AEO-7 and salt(NaCl,Na2SO4, Na3PO4),adding L-phenylalanine content of extracts,extraction time,extraction temperature were investigated. The results showed that the optimal conditions of AEO-7/Na3PO4,aqueous two-phase extraction of L-phenylalanine is volume concentration when AEO-7 was 8%,concentration of Na3PO4·12H2O for 85 g/L,temperature 40℃,concentration of L-phenylalanine is 0.532 8 g/L,time 60 min extraction of L-phenylalanine rate can reach 98.7%,the distribution coefficient of 15.3.%该文对氨基酸萃取液在非离子表面活性剂双水相体系中的萃取分配相行为进行研究。采用脂肪醇聚氧乙烯醚AEO-7/盐双水相萃取L-苯丙氨酸,考察了加盐(NaCl、Na2SO4、Na3PO4)、AEO-7含量、萃取时间、加入萃取物L-苯丙氨酸的含量以及萃取温度对双水相及萃取分离L-苯丙氨酸的影响。结果表明,AEO-7/Na3PO4双水相萃取L-苯丙氨酸的适宜条件是当AEO-7的体积浓度为8%,Na3PO4·12H2O的质量浓度为85 g/L,温度为40℃,L-苯丙氨酸的质量浓度为0.5328 g/L,时间为60 min时L-苯丙氨酸的萃取率可以达到98.7%,分配系数为15.3。

  20. Interfacial thermodynamics and electrochemistry of protein partitioning in two-phase systems.

    NARCIS (Netherlands)

    Fraaije, J.G.E.M.

    1987-01-01

    The subject of this thesis is protein partition between an aqueous salt solution and a surface or an apolair liquid and the concomitant co-partition of small ions. The extent of co-partitioning determines the charge regulation in the protein partitioning process.Chapters 2 and 3 deal with phenomenol

  1. Particle sizing in dense two-phase droplet systems by ultrasonic attenuation and velocity spectra

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Size and size distribution of particles in particulate two-phase flow play an important role in a wide variety of industrial areas,while their measurement still remains a hard task till now.Ultrasonic wave as a mechanical vibration contains plenty of information about medium when it passes through.Thus the size distribution could be extracted from the measured ultrasonic attenuation and velocity spectra by means of well established models and data processing techniques.This paper contributes to the extraction of information of droplet size of a two-phase fat emulsion simultaneously from signals of broad-band ultrasonic attenuation and velocity spectra.According to the formulated single particle scattering model,the relationship between particle size distribution and ultrasonic spectrum is estab-lished.The sensitivities of ultrasonic spectra to the variation of particle size are illustrated.Distin-guishing features for attenuation and velocity spectra are summarized.Demonstration calculations of inversion by optimum regularization factor method are carried out to yield the typical numerical results for discussion.Based on the proposed inversion algorithm and theoretical model,a fat emulsion sam-ple with a volume fraction up to 20% is measured and analyzed.To validate the proposed ultrasonic spectrum particle sizing method,the results are compared to those obtained from optical measure-ment.

  2. Particle sizing in dense two-phase droplet systems by ultrasonic attenuation and velocity spectra

    Institute of Scientific and Technical Information of China (English)

    SU MingXu; CAI XiaoShu; XUE MingHua; DONG LiLi; XU Feng

    2009-01-01

    Size and size distribution of particles in particulate two-phase flow play an important role in a wide va-riety of industrial areas, while their measurement still remains a hard task till now. Ultrasonic wave as a mechanical vibration contains plenty of information about medium when it passes through. Thus the size distribution could be extracted from the measured ultrasonic attenuation and velocity spectra by means of well established models and data processing techniques. This paper contributes to the ex-traction of information of droplet size of a two-phase fat emulsion simultaneously from signals of broad-band ultrasonic attenuation and velocity spectra. According to the formulated single particle scattering model, the relationship between particle size distribution and ultrasonic spectrum is estab-lished. The sensitivilles of ultrasonic spectra to the variation of particle size are illustrated. Distin-guishing features for attenuation and velocity spectra are summarized. Demonstration calculations of inversion by optimum regularization factor method are carried out to yield the typical numerical results for discussion. Based on the proposed inversion algorithm and theoretical model, a fat emulsion sam-ple with a volume fraction up to 20% is measured and analyzed. To validate the proposed ultrasonic spectrum particle sizing method, the results are compared to those obtained from optical measure-ment.

  3. Two-phase Flow of Liquid-gas in Diesel Fuel Injection System and Their Effect on Engine Performances

    Institute of Scientific and Technical Information of China (English)

    Yongling He; Zhihe Zhao; Jianxin Liu; Huiyong Du; Min Li; Yongping Zong

    2001-01-01

    In this paper, by using high-speed camera, CCD camera, signal and graph acquisition system, and other experimental instruments, investigation on liquid-gas two-phase flow in diesel fuel injection system and their effect on engine performances were made. Emerging and bursting of cavitation in the cavity above pump delivery valve, in injection pipe, and in fuel trough of injector of the fuel injection system were observed and mechanism of cavitation were discussed. Effects of liquid-gas two-phase flow on propagation velocity of pressure wave of the system and on irregular injection were analyzed. Two types of cavitation, long living time cavitation and short living time cavitation, in the cavity above pump delivery valve of diesel fuel injection system were observed.

  4. Low Energy Consumption Technique for Processing Rapeseed with Two-phase Extraction System without Ammonia

    Institute of Scientific and Technical Information of China (English)

    Shi Meiren; Qin Jinping; SQian Renyuan

    2000-01-01

    the mother liquid of methanol phase obtained from rapeseed two-phase extraction process can directly be reused in large amounts to process rapeseed again together with some fresh methanol phase, so long as it is treated with a litter of proper additives in advance. The ratio of the reused mother liquid may be more than 3/ 4 of the total amount of the methanol phase needed for processing rapeseed, so the energy consumption can be decreased tremendously. The meal obtained by use of the reused mother liquid keeps the quality as good as those obtained by use of totally fresh methanol phase with light color, weak taste, crispness, good palatability, high protein content, and a low level of glucosinolates much more less than that stipulated by the State for the fodder of grade A.

  5. Two-phase anaerobic digestion within a solid waste/wastewater integrated management system.

    Science.gov (United States)

    De Gioannis, G; Diaz, L F; Muntoni, A; Pisanu, A

    2008-01-01

    A two-phase, wet anaerobic digestion process was tested at laboratory scale using mechanically pre-treated municipal solid waste (MSW) as the substrate. The proposed process scheme differs from others due to the integration of the MSW and wastewater treatment cycles, which makes it possible to avoid the recirculation of process effluent. The results obtained show that the supplying of facultative biomass, drawn from the wastewater aeration tank, to the solid waste acidogenic reactor allows an improvement of the performance of the first phase of the process which is positively reflected on the second one. The proposed process performed successfully, adopting mesophilic conditions and a relatively short hydraulic retention time in the methanogenic reactor, as well as high values of organic loading rate. Significant VS removal efficiency and biogas production were achieved. Moreover, the methanogenic reactor quickly reached optimal conditions for a stable methanogenic phase. Studies conducted elsewhere also confirm the feasibility of integrating the treatment of the organic fraction of MSW with that of wastewater. PMID:18191559

  6. Quantitative study on experimentally observed poroelastic behavior of Berea sandstone in two-phase fluid system

    Science.gov (United States)

    Goto, Hiroki; Aichi, Masaatsu; Tokunaga, Tomochika; Yamamoto, Hajime; Ogawa, Toyokazu; Aoki, Tomoyuki

    2014-08-01

    Coupled two-phase fluid flow and poroelastic deformation of Berea sandstone is studied through laboratory experiment and numerical simulation. In the experiment, compressed air was infiltrated from the bottom of a water-saturated cylindrical Berea sandstone sample under hydrostatic external stress condition. Both axial and circumferential strains at half the height of the sample showed sudden extension and monotonic and gradual extension afterward. Numerical simulation based on thermodynamically consistent constitutive equations was conducted in order to quantitatively analyze the experimental results. In a simulation assuming isotropy of material properties, the volumetric discharge rate of water at the outlet and one of the axial, circumferential, and volumetric strains at half the height of the sample were reproduced well by each parameter set, while the other two strains were not. When introducing transverse isotropy, all the experimental data were reproduced well. In addition, the effect of saturation dependency of Bishop's effective stress coefficient on the deformation behavior of porous media was discussed, and it was found that strains, both axial and circumferential, are sensitive to the coefficient.

  7. Mars Aqueous Processing System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Mars Aqueous Processing System (MAPS) is an innovative method to produce useful building materials from Martian regolith. Acids and bases produced from the regolith...

  8. Mars Aqueous Processing System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Mars Aqueous Processing System (MAPS) is a novel technology for recovering oxygen, iron, and other constituents from lunar and Mars soils. The closed-loop...

  9. Biogas production from anaerobic co-digestion of food waste with dairy manure in a two-phase digestion system.

    Science.gov (United States)

    Li, Rongping; Chen, Shulin; Li, Xiujiu

    2010-01-01

    Co-digestion of food waste and dairy manure in a two-phase digestion system was conducted in laboratory scale. Four influents of R0, R1, R2, and R3 were tested, which were made by mixing food waste with dairy manure at different ratios of 0:1, 1:1, 3:1, and 6:1, respectively. For each influent, three runs of experiments were performed with the same overall hydraulic retention time (HRT) of 13 days but different HRT for acidification (1, 2, and 3 days) and methanogenesis (12, 11, and 10 days) in two-phase digesters. The results showed that the gas production rate (GPR) of co-digestion of food waste with dairy manure was enhanced by 0.8-5.5 times as compared to the digestion with dairy manure alone. Appropriate HRT for acidification was mainly determined by the biodegradability of the substrate digested. Three-, 2-, and 1-day HRT for acidification were found to be optimal for the digestion of R0, R1, and R2/R3, respectively, when overall HRT of 13 days was used. The highest GPR of 3.97 L/L.day was achieved for R3(6:1) in Run 1 (1 + 12 days), therefore, the mixing ratio of 6:1 and HRT of 1 day for acidification were considered to be the optimal ones and thus recommended for co-digestion of food waste and dairy manure. There were close correlations between degradation of organic matters and GPR. The highest VS removal rate was achieved at the same HRT for acidification and mixing ratio of food waste and dairy manure as GPR in the co-digestion. The two-phase digestion system showed good stability, which was mainly attributed to the strong buffering capacity with two-phase system and the high alkalinity from dairy manure when co-digested with food waste. PMID:19214795

  10. Effect of Mechanical Stress on Magnetic States and Hysteresis Characteristics of a Two-Phase Nanoparticles System

    Directory of Open Access Journals (Sweden)

    Leonid Lazarevich Afremov

    2013-01-01

    Full Text Available In terms of the two-phase nanoparticles model, the effect of mechanical stress on the magnetic state of both uniaxial and multiaxial heterophase magnetic is investigated. The spectrum of critical fields of reversal of phases' magnetic moments was calculated and phase diagrams were drawn to assess the effect of mechanical stress on the degree of metastability of two-phase nanoparticles' magnetic states. By the example of epitaxial cobalt-coated -Fe2O3 particles, a theoretical analysis of the effect of uniaxial mechanical stress on the magnetization of a system of noninteracting heterophase nanoparticles is investigated. It was shown that tension reduced and compression increased coercive force , while the residual saturation magnetization was not changed under the influence of mechanical stress.

  11. Surfactant-coated Candida rugosa Lipase as Catalyst for Hydrolysis of Olive Oil in Solvent-Free Two-Phase System

    Institute of Scientific and Technical Information of China (English)

    宋宝东; 丁辉; 吴金川; HayashiY.; TalukderMMR; 王世昌

    2003-01-01

    The surfactant-coated Candida rugosa lipase was used as catalyst for hydrolysis of olive oil in two-phase system consisting of olive oil and phosphate buffer without organic solvent. For both the coated and native lipases,the optimal buffer/oil volume ratio of 1.0, aqueous pH 6.8 and reaction temperature 30℃ were determined. The maximum activity of the coated lipase was ca 1.3 times than that of the native lipase. The half-life of the coated lipase in olive oil and the native lipase in phosphate buffer was ca 9 h and 12 h, and the final residual activity was 27% and 20% of their initial values, respectively. The final substrate conversion by the coated lipase was ca 20% higher than that of the native lipase.

  12. Partitioning behavior of laccase from Lentinus polychrous Lev in aqueous two phase systems

    Directory of Open Access Journals (Sweden)

    Palapum Khunthongjan

    2012-02-01

    Full Text Available The water current has used as the energy resource for long time however its velocity is very low therefore there arenot found in wide range of uses. This study purposes accelerate water velocity by installing diffuser. The problems wereanalyzed by one dimension analysis and computational fluid dynamics (CFD; the domain covers the diffuser and turbinewhich substituted by porous jump condition is install inside. The flow was identified as axisymmetric steady flow, the inletboundary is identified as uniform flow, all simulation use the same size of diffuser, only the diffuser angles are vary. The resultsshow that velocities of water current in diffuser are increase when the diffuser angle are widen. The angle of diffuser is 20°,the velocity is increase to 1.96 times, compared to free stream velocity. If the angle was about 0-20° and 50-70° the forcetoward diffuser became high instantly; where as the force toward the rotor will be still and the maximum rate of diffuseraugmentation possibly was 3.62 and rotor power coefficient was 2.14.

  13. Extraction of vanillin using ionic-liquid-based aqueous two-phase systems

    OpenAIRE

    Cláudio, Ana Filipa M.; Freire, Mara G.; Freire, Carmen S. R.; Silvestre, Armando J. D.; Coutinho, João A. P.

    2010-01-01

    To explore proper extractive solvents and to design an optimized separation process it is highly imperative to understand the molecular-based phenomena governing the solutes partitioning. Moreover, the development of new techniques for the biomolecules separation and purification, while maintaining their functional characteristics unchanged, is still ongoing. Therefore, in this work, the partition coefficients of vanillin, a compound with well-known organoleptic properties, were determined us...

  14. Enzymatic synthesis of polyol esters in aqueous-organic two-phase systems.

    NARCIS (Netherlands)

    Janssen, A.E.M.

    1993-01-01

    The last decade increasingly attention is paid to lipases as catalysts for synthesis of components, such as fatty acid-based surfactants, flavors, edible oil equivalents, monomers and polymers, and amides. In this thesis, the lipase-catalyzed esterification of polyols and fatty acids is described. T

  15. Slug flow transitions in horizontal gas/liquid two-phase flows. Dependence on channel height and system pressure for air/water and steam/water two-phase flows

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Hideo [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1996-05-01

    The slug flow transitions and related phenomena for horizontal two-phase flows were studied for a better prediction of two-phase flows that typically appear during the reactor loss-of-coolant accidents (LOCAs). For better representation of the flow conditions experimentally, two large-scaled facility: TPTF for high-pressure steam/water two-phase flows and large duct test facility for air/water two-phase flows, were used. The visual observation of the flow using a video-probe was performed in the TPTF experiments for good understanding of the phenomena. The currently-used models and correlations based mostly on the small-scale low-pressure experiments were reviewed and improved based on these experimental results. The modified Taitel-Dukler model for prediction of transition into slug flow from wavy flow and the modified Steen-Wallis correlation for prediction of onset of liquid entrainment from the interfacial waves were obtained. An empirical correlation for the gas-liquid interfacial friction factor was obtained further for prediction of liquid levels at wavy flow. The region of slug flow regime that is generally under influences of the channel height and system pressure was predicted well when these models and correlations were applied together. (author). 90 refs.

  16. Stratified single- and two phase flows in horizontal tubes and tube-tank systems

    International Nuclear Information System (INIS)

    Serviceability of the accident heat removal system from containment shell of NPP is investigated. Results of experimenters with the model of the system are presented. Regimes of unstable operation of the heat removal system because of rise of hydraulic hammers and vibration of the equipment were detected. Reasons of these events were determined. It is noted that instability of the operation of the system is connected with infiltrate of relatively cold coolant from tank-cooler in overflow pipeline

  17. Two-phase low-energy N-modular redundancy for hard real-time multi-core systems

    OpenAIRE

    Salehi, Mohammad; Ejlali, Alireza; Al-Hashimi, Bashir M.

    2015-01-01

    This paper proposes an N-modular redundancy (NMR) technique with low energy-overhead for hard real-time multi-core systems. NMR is well-suited for multi-core platforms as they provide multiple processing units and low-overhead communication for voting. However, it can impose considerable energy overhead and hence its energy overhead must be controlled, which is the primary consideration of this paper. For this purpose the system operation can be divided into two phases: indispensable phase an...

  18. Separated two-phase flow regime parameter measurement by a high speed ultrasonic pulse-echo system.

    Science.gov (United States)

    Masala, Tatiana; Harvel, Glenn; Chang, Jen-Shih

    2007-11-01

    In this work, a high speed ultrasonic multitransducer pulse-echo system using a four transducer method was used for the dynamic characterization of gas-liquid two-phase separated flow regimes. The ultrasonic system consists of an ultrasonic pulse signal generator, multiplexer, 10 MHz (0.64 cm) ultrasonic transducers, and a data acquisition system. Four transducers are mounted on a horizontal 2.1 cm inner diameter circular pipe. The system uses a pulse-echo method sampled every 0.5 ms for a 1 s duration. A peak detection algorithm (the C-scan mode) is developed to extract the location of the gas-liquid interface after signal processing. Using the measured instantaneous location of the gas/liquid interface, two-phase flow interfacial parameters in separated flow regimes are determined such as liquid level and void fraction for stratified wavy and annular flow. The shape of the gas-liquid interface and, hence, the instantaneous and cross-sectional averaged void fraction is also determined. The results show that the high speed ultrasonic pulse-echo system provides accurate results for the determination of the liquid level within +/-1.5%, and the time averaged liquid level measurements performed in the present work agree within +/-10% with the theoretical models. The results also show that the time averaged void fraction measurements for a stratified smooth flow, stratified wavy flow, and annular flow qualitatively agree with the theoretical predictions.

  19. A Novel Flow Measurement System for Cryogenic Two-Phase Flow Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Flow rate measurements for cryogenic propellants are required for spacecraft and space exploration systems. Such a requirement has been hampered by lack of fast and...

  20. Interfacial Area and Interfacial Transfer in Two-Phase Flow Systems (Volume II. Chapters 6-10)

    Energy Technology Data Exchange (ETDEWEB)

    Guo, T.; Park, J.; Kojasoy, G.

    2003-03-15

    Experiments were performed on horizontal air-water bubbly two-phase flow, axial flow, stratified wavy flow, and annular flow. Theoretical studies were also undertaken on interfacial parameters for a horizontal two-phase flow.

  1. Interfacial Area and Interfacial Transfer in Two-Phase Flow Systems (Volume III. Chapters 11-14)

    Energy Technology Data Exchange (ETDEWEB)

    Guo, T.; Park, J.; Kojasoy, G.

    2003-03-15

    Experiments were performed on horizontal air-water bubbly two-phase flow, axial flow, stratified wavy flow, and annular flow. Theoretical studies were also undertaken on interfacial parameters for a horizontal two-phase flow.

  2. Interfacial Area and Interfacial Transfer in Two-Phase Flow Systems (Volume I. Chapters 1-5)

    Energy Technology Data Exchange (ETDEWEB)

    Guo, T.; Park, J.; Kojasoy, G.

    2003-03-15

    Experiments were performed on horizontal air-water bubbly two-phase flow, axial flow, stratified wavy flow, and annular flow. Theoretical studies were also undertaken on interfacial parameters for a horizontal two-phase flow.

  3. Interfacial Area and Interfacial Transfer in Two-Phase Flow Systems (Volume IV. Chapters 15-19)

    Energy Technology Data Exchange (ETDEWEB)

    Guo, T.; Park, J.; Kojasoy, G.

    2003-03-15

    Experiments were performed on horizontal air-water bubbly two-phase flow, axial flow, stratified wavy flow, and annular flow. Theoretical studies were also undertaken on interfacial parameters for a horizontal two-phase flow.

  4. Determination of Vitamin B6 by Fluorimetry after Aqueous Two-Phase Extraction Based on Ionic Liquid%离子液体双水相萃取荧光法测定维生素B6

    Institute of Scientific and Technical Information of China (English)

    谢秀娟; 张振新

    2011-01-01

    Based on the fact that water-miscible sol vent, such as ionic liquid, can be used to form aqueous two-phase system for extraction of analytes in the presence of salts, ionic liquid-salt system of ionic liquid( [Bmim]Br )and(NH4)2SO4 was developed for the determination of trace vitamin B6 coupled with fluorimetry after aqueous two-phase extraction. Factors that affect the extraction efficiencies of vitamin B6 including pH, the amount of extractant and extraction time were well studied. Under the optimal conditions, I. E. , λex/λem = 342/418 nm,pH = 8. 69, 1. 3 mL ionic liquid, 2. 8 g ammonium sulfate and 3 min of extraction, the extraction method presented a linear range of 1. 6×10-7~l. 04×10-5 g/L with a detection limit of 4. 8 × 10-7 g/L.%基于离子液体在盐的作用下能够形成双水相,用于目标物质的萃取,提出了离子液体-硫酸铵双水相萃取、荧光法测定痕量维生素B6的新方法.实验探讨了影响维生素B6萃取率的主要因素,如酸度、萃取剂的用量、时间等.在最适条件下,即λex/λem=342/418 nm,pH=8.69,离子液体和硫酸铵的用量分别为1.3mL、2.8g,萃取3 min时,体系测定维生素B6的线性范围为1.6×10-7~1.04×10-5 g/L,检出限为4.8×10-7 g/L.

  5. Model selection support expert system for numerical simulation of liquid-vapor two phase flow

    International Nuclear Information System (INIS)

    A model selection support expert system has been developed to accomplish the construction of suitable mathematical model consistent with the purpose and condition for a thermal-hydraulic calculation of nuclear power plants. This paper describes two extensions of the expert system: 1) estimation of outline of plant behavior at a target simulation case by the case-based reasoning, and 2) relaxation of incompleteness of knowledge base for model selection by domain knowledge. From the results of sample plant behavior estimations, the case-based reasoning is shown to be successfully applied. On the other hand, the relaxation by domain knowledge is considered to be inevitable for the usage of incomplete knowledge base, although this technique has not been implemented in the model selection support expert system yet. (author)

  6. Phase separation model analysis of gas-liquid two phase flow in the zones of influence in horizontal pipeline system

    International Nuclear Information System (INIS)

    A computational program is proposed to calculate the two-phase flow in the T type and Y type branch by using a mechanistic model based on the idea that the gas and liquid flows being extracted into the side branch come from the 'influence zones' bounded by 'dividing streamline'. A number of numerical calculations are carried out to give predictive results in good agreement with others' experiment work on this field. The calculation shows that the branch angle is one of the main factors effecting the phase separation in branch type systems. Meanwhile the influences of inlet parameter X1 are also discussed

  7. Primitive Liquid Water of the Solar System in an Aqueous Altered Carbonaceous Chondrite

    Science.gov (United States)

    Tsuchiyama, A.; Miyake, A.; Kitayama, A.; Matsuno, J.; Takeuchi, A.; Uesugi, K.; Suzuki, Y.; Nakano, T.; Zolensky, M. E.

    2016-01-01

    Non-destructive 3D observations of the aqueous altered CM chondrite Sutter's Mill using scanning imaging x-ray microscopy (SIXM) showed that some of calcite and enstatite grains contain two-phase inclusion, which is most probably composed of liquid water and bubbles. This water should be primitive water responsible for aqueous alteration in an asteroid in the early solar system.

  8. Dynamic Performances in Sensorless System with Two-Phase Induction Motor

    Directory of Open Access Journals (Sweden)

    CRĂCIUNAŞ Gabriela

    2013-10-01

    Full Text Available In this paper is treated one of the most effective and widely used methods to obtain good dynamic performances for AC motor namely rotor flux direct field oriented control. A key role in achieving such adjustment is played by the rotor flux estimator. This on the one hand provides the absolute value which is used in the flux feedback control loop and on the other hand it gives the position of the rotor flux relative to the stator system. In the block diagram of the driving system with direct field oriented adjusting control there are used estimators derived directly from the machine equations. Using Matlab/Simulink simulation environment applied for a two-phaseinduction motor model, simulations were made for different imposed speeds and the characteristics of each estimator block diagram were highlighted.

  9. 1-Dodecene Hydroformylation Catalyzed by Water SolubleRhodium Phosphine Complex in Two-Phase System

    Institute of Scientific and Technical Information of China (English)

    黎耀忠; 陈华; 陈骏如; 程溥明; 胡家元; 李贤均

    2001-01-01

    1-Dodecene hydroformylation catalyzed by water solublerhodium complex [PhCI(CO)(TPPTS)2] was studied in the presence of TPPTS [P(m-C6H4SO3Na)3] and CTAB (cetylirbmethyl ammonium). The influence of reaction parameters was discussed in detail based on micelle effect in biphasic system. The modification for the microcircumstance of micelle interface was conducted by the introduction of a catalyst promoter TPPDS [PhP(m-C6H4SO3Na)2] into the reaction solution. A synergistic effect between TPPDS and TPPTS on the regioselectivotu of 1-dodecene hydroformylation was observed.The selectivity of linear aldehyde in the products was so high as 95.7% at the molar ratio of TPPDS]/[TPPTS] = 0.5.

  10. Numerical Simulation of One- and Two-Phase Flows in Propulsion Systems

    Science.gov (United States)

    Gilinsky, Mikhail; Verma, Arun; Hardin, Jay C.; Banerjee, Debrup; Blankson, Isaiah M.; Hendricks, Robert C.; Shvets, Alexander I.

    2003-01-01

    Four subprojects were conducted using analytical methods, numerical simulation and experimental tests: (A) Shock wave mitigation by spike-shaped blunt bodies with application for the purpose of drag, lift and longitudinal momentum optimization. The main result in this subproject is: application of a single needle against a supersonic flow provides higher benefits for blunt body drag reduction and heat transfer to the body than the application of multiple needles. (B) Solid particles, liquid and air jet injection through the front of a blunt body against a supersonic flow. In this case, the research conducted and analysis of multiple previous investigations in this area have shown essential benefits and preferable application of solid particle injection. (C) Comparison of different methods of fuel injection into supersonic duct flows. Preliminary numerical simulations and theoretical analysis show promising results for Telescope-shaped inlet applications in SCRAMJET; and (D) Development of an acoustic source location method for different applications including propulsion systems.

  11. Numerical Modeling on Two phase Fluid flow in a Coupled Fracture-Skin-Matrix System

    Science.gov (United States)

    Valsala Kumari, R.; G, S. K.

    2015-12-01

    Multiphase flow modeling studies below the ground surface is very essential for designing suitable remediation strategies for contaminated aquifers and for the development of petroleum and geothermal reservoirs. Presence of fractured bedrock beneath the ground surface will make multiphase flow process more complex due to its highly heterogeneous nature. A major challenge in modeling flow within a fractured rock is to capture the interaction between the high permeability fracture and the low permeability rock-matrix. In some instances, weathering and mineral depositions will lead to formation of an additional layer named fracture-skin at the fracture-matrix interface. Porosity and permeability of fracture-skin may significantly vary from the adjacent rock matrix and this variation will result in different flow and transport behavior within the fracture-skin. In the present study, an attempt has been made to model simultaneous flow of two immiscible phases (water and LNAPL) in a saturated coupled fracture-skin-matrix system. A fully-implicit finite difference model has been developed to simulate the variation of pressure and saturation of fluid phases along the fracture and within the rock-matrix. Sensitivity studies have been done to analyze the effect of change of various fracture-skin parameters such as porosity, diffusion coefficient and thickness on pressure and saturation distribution of both wetting and non-wetting fluid phases. It can be concluded from the study that the presence of fracture-skin is significantly affecting the fluid flow at the fracture-matrix interface and it can also be seen from the study that the flow behavior of both fluid phases is sensitive to fracture-skin parameters.

  12. Comparative assessment of olive oil mill effluents from three-phase and two-phase systems, treated for hydrogen production.

    Science.gov (United States)

    Rouvalis, A; Iliopoulou-Georgudaki, J

    2010-10-01

    By-products of a two-phase and a three-phase olive oil mill process treated in an anaerobic fermentation system for hydrogen production, were evaluated by three bioassays: the zebrafish Danio rerio embryo test and two microbiotests, Thamnotoxkit F and Daphtoxkit F™ pulex. Samples from both processes were classified as "very toxic" with LC(50) values ranging from 1.52% (T. platyurus 24 h test) to 4.48% (D. pulex 48 h-LC₅₀). Toxicity values were differently correlated to physicochemical parameters showing different degree of influence. The treated effluents of both process systems remained very toxic showing the necessity for further treatment, aiming to environmentally safe discharges.

  13. Porcine acute liver failure model established by two-phase surgery and treated with hollow fiber bioartificial liver support system

    Institute of Scientific and Technical Information of China (English)

    Yi Gao; Ning Mu; Xiao-Ping Xu; Yan Wang

    2005-01-01

    AIM: To establish a highly reproducible animal model of acute liver failure (ALF), for assessing theeffect of bioartificial liver support system (BALSS).METHODS: A two-phase complete liver devascularization procedure was performed in eight loco-hybrid pigs. Blood biochemical index and liver biopsy were studied every 2 h after surgery, and survival time was recorded. The BALSS constructed with high volume recirculating technique was a hollow fiber circulating system consisting of a hepatocyte reactor-hollow fiber module inoculated with microcarrieradhering hepatocytes, and a double pump, heparinized,thermostabilized, micro-capsulized activated carbonadsorbing plasmapheresis system. Twelve pigs undergoing two-phase surgery were randomized into: control group (perfused without hepatocytes, n = 6) and treatment group (perfused with hepatocytes, n = 6). Intergroup liver biochemical indexes, survival time, and liver pathological changes were analyzed at regular intervals.RESULTS: Two-phase surgery was performed in all the experimental pigs, and there was no obvious difference between their biochemical indexes. After 3 h of phase Ⅱ surgery, ammonia (Amm) increased to (269±37) μmol/L.After 5 h of the surgery, fibrinogen (Fib) decreased to (1.5±0.2) g/L. After 7 h of the surgery, ALT, AST, Tbil and PT were (7.6±1.8) nka/L, (40±5) nka/L, (55±8) μmol/L and (17.5±1.7) nka/L respectively. After 9 h of surgery, ALB and Cr were (27±4) g/L and (87±9) μmol/L. After 13 h of surgery, BUN was (3.5±0.9) μmol/L. All the above values were different from those determined before surgery.Survival time of pigs averaged 13.5±1.4 h. ALF pigs in the other group were treated with BALSS. The comparison analysis between the treated and control animals showed the changes of Tbil, PT, Alb, BUN, Cr, Fib, and Amm (P<0.01), but there was no change of ALT and AST. The survival time was statistically different (P<0.01), and there was no significant difference in histological changes

  14. Two-phase ozonation of chlorinated organics

    International Nuclear Information System (INIS)

    In the last few years the amount of research being conducted in the field of single-phase ozonation has grown extensively. However, traditional aqueous-phase ozonation systems are limited by a lack of selective oxidation potential, low ozone solubility in water, and slow intermediate decomposition rates. Furthermore, ozone may decompose before it can be utilized for pollutant destruction since ozone can be highly unstable in aqueous solutions. Naturally occurring compounds such as NaHCO3 also affect ozone reactions by inhibiting the formation of OH-free radicals. To compensate for these factors, excess ozone is typically supplied to a reactor. Since ozone generation requires considerable electric power consumption (16 - 24 kWh/kg of O3), attempts to enhance the ozone utilization rate and stability should lead to more efficient application of this process to hazardous waste treatment. To improve the process, ozonation may be more efficiently carried out in a two-phase system consisting of an inert solvent (saturated with O3) contacted with an aqueous phase containing pollutants. The non-aqueous phase must meet the following criteria: (1) non-toxic, (2) very low vapor pressure, (3) high density (for ease of separation), (4) complete insolubility in water, (5) reusability, (6) selective pollutant extractability, (7) high oxidant solubility, and (8) extended O3 stability. Previously published studies (1) have indicated that a number of fluorinated hydrocarbon compounds fit these criteria. For this project, FC40 (a product of 3M Co.) was chosen due to its low vapor pressure (3 mm Hg) and high specific gravity (1.9). The primary advantages of the FC40 solvent are that it is non-toxic, reusable, has an ozone solubility 10 times that of water, and that 85 % of the ozone remains in the solvent even after 2 hours. This novel two-phase process has been utilized to study the rapid destruction of organic chlorine compounds and organic mixtures

  15. Modeling and investigation of refrigeration system performance with two-phase fluid injection in a scroll compressor

    Science.gov (United States)

    Gu, Rui

    Vapor compression cycles are widely used in heating, refrigerating and air-conditioning. A slight performance improvement in the components of a vapor compression cycle, such as the compressor, can play a significant role in saving energy use. However, the complexity and cost of these improvements can block their application in the market. Modifying the conventional cycle configuration can offer a less complex and less costly alternative approach. Economizing is a common modification for improving the performance of the refrigeration cycle, resulting in decreasing the work required to compress the gas per unit mass. Traditionally, economizing requires multi-stage compressors, the cost of which has restrained the scope for practical implementation. Compressors with injection ports, which can be used to inject economized refrigerant during the compression process, introduce new possibilities for economization with less cost. This work focuses on computationally investigating a refrigeration system performance with two-phase fluid injection, developing a better understanding of the impact of injected refrigerant quality on refrigeration system performance as well as evaluating the potential COP improvement that injection provides based on refrigeration system performance provided by Copeland.

  16. Comparative performance and microbial community of single-phase and two-phase anaerobic systems co-digesting cassava pulp and pig manure

    DEFF Research Database (Denmark)

    Panichnumsin, P.; Ahring, B.K.; Nopharatana, A.;

    2010-01-01

    In this study, we illustrated the performance and microbial community of single- and two-phase systems anaerobically co-digesting cassava pulp and pig manure. The results showed that the volatile solid reduction and biogas productivity of two-phase CSTR were 66 ± 4% and 2000 ± 210 ml l-1 d-1, while...... those of singlephase CSTR were 59 ± 1% and 1670 ± 60 ml l-1 d-1, respectively. Codigestion in two-phase CSTR gave higher 12% solid degradation and 25% methane production than single-phase CSTR. Phylogenetic analysis of 16S rDNA clone library revealed that the Bacteroidetes were the most abundant group...

  17. Immobilized metal-ion affinity partitioning of NAD(+)-dependent dehydrogenases in poly(ethylene glycol)-dextran two-phase systems.

    Science.gov (United States)

    Pesliakas, H; Zutautas, V; Baskeviciute, B

    1994-08-26

    Affinity partitioning of yeast alcohol dehydrogenase (YADH), lactate dehydrogenase from rabbit muscle (MLDH) and lactate and malate dehydrogenases from pig heart (HLDH and HMDH, respectively) were studied in aqueous two-phase systems containing metal ions (Cu2+, Ni2+, Zn2+ and Cd2+) chelated by iminodiacetate-poly(ethylene glycol) (IDA-PEG). The partitioning behaviour of the enzymes in the presence of Cu(II)-IDA-PEG was studied as a function of the concentration of NaCl, the pH of the medium and the concentration of added selected agents. It was demonstrated that the partition effect (delta log K) of dehydrogenases in the presence of Cu(II)-IDA-PEG and the affinity of enzymes for immobilized Cu2+ ions increases in the order MLDH > YADH > HMDH > or = HLDH. It was shown that the determined variations in the enzyme affinities for Cu(II)-IDA-PEG might be related to the differences in the content of histidine residues accessible to the solvent.

  18. An investigation into the flow behavior of a single phase gas system and a two phase gas/liquid system in normal gravity with nonuniform heating from above

    Science.gov (United States)

    Disimile, Peter J.; Heist, Timothy J.

    1990-01-01

    The fluid behavior in normal gravity of a single phase gas system and a two phase gas/liquid system in an enclosed circular cylinder heated suddenly and nonuniformly from above was investigated. Flow visualization was used to obtain qualitative data on both systems. The use of thermochromatic liquid crystal particles as liquid phase flow tracers was evaluated as a possible means of simultaneously gathering both flow pattern and temperature gradient data for the two phase system. The results of the flow visualization experiments performed on both systems can be used to gain a better understanding of the behavior of such systems in a reduced gravity environment and aid in the verification of a numerical model of the system.

  19. Evidence for Two Phases of Galaxy Formation from Radial Trends in the Globular Cluster System of NGC 1407

    CERN Document Server

    Forbes, Duncan; Strader, Jay; Romanowsky, Aaron; Brodie, Jean; Foster, Caroline

    2011-01-01

    Here we present the colours of individual globular clusters (GCs) around the massive elliptical galaxy NGC 1407 out to a projected galactocentric radius of 140 kpc or 17 galaxy effective radii (R$_e$). Such data are a proxy for the halo metallicity. We find steep, and similar, metallicity gradients of ~ -0.4 dex per dex for both the blue (metal-poor) and red (metal-rich) GC subpopulations within 5-8.5 R_e (40-70 kpc). At larger radii the mean GC colours (metallicity) are constant. A similar behaviour is seen in a wide-field study of M87's GC system, and in our own Galaxy. We interpret these radial metallicity trends to indicate an inner region formed by early in-situ dissipative processes and an outer halo formed by ongoing accretion of low mass galaxies and their GCs. These results provide observational support for the model of galaxy formation whereby massive galaxies form inside-out in two phases. We have also searched the literature for other massive early-type galaxies with reported GC metallicity gradie...

  20. Study on the Intermediate in the o-Phenylenediamine Oxidative Reaction Using Hemoglobin as A Mimetic Peroxidase in Aqueous-Organic Two Phase

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Hemoglobin was used as a mimetic enzyme for peroxidase to catalyze the oxidative reaction ofo-phenylenediamine with H2O2 which functioned as an oxidant. The relationship between physicochemicalproperties of the intermediate and enzymatic activity of hemoglobin was studied. Since the solubility of theintermediate in the reaction is higher in butanol phase than in water phase, the intermediate itself diffusedfrom the aqueous phase to the butanol phase. The experimental results showed that the rate of product andthe stability of intermediate were associated with the temperature and the pH value of the buffer. The for-mation rate of intermediate and half-life period reveal the maximal in pH7, nevertheless, the whole rate ofthe catalytic reaction is the greatest in pH5, which the ratio of the initial rate in final product formationcompared to that intermediate formation is the greatest.

  1. Improvements in Neutronics/Thermal-Hydraulics Coupling in Two-Phase Flow Systems Using Stochastic-Mixture Transport Models

    CERN Document Server

    Palmer, T S

    2003-01-01

    In this NEER project, researchers from Oregon State University have investigated the limitations of the treatment of two-phase coolants as a homogeneous mixture in neutron transport calculations. Improved methods of calculating the neutron distribution in binary stochastic mixtures have been developed over the past 10-15 years and are readily available in the transport literature. These methods are computationally more expensive than the homogeneous (or atomic mix) models, but can give much more accurate estimates of ensemble average fluxes and reaction rates provided statistical descriptions of the distributions of the two materials are know. A thorough review of the two-phase flow literature has been completed and the relevant mixture distributions have been identified. Using these distributions, we have performed Monte Carlo criticality calculations of fuel assemblies to assess the accuracy of the atomic mix approximation when compared to a resolved treatment of the two-phase coolant. To understand the ben...

  2. Numerical modelling of the impact of a liquid drop on the surface of a two-phase fluid system

    Science.gov (United States)

    Sochan, Agata; Lamorski, Krzysztof; Bieganowski, Andrzej; Ryżak, Magdalena

    2014-05-01

    The aim of the study was validation of a numerical model of the impact of a liquid drop on the surface of a two-phase system of immiscible fluids. The drop impact phenomenon was recorded using a high-speed camera (Vision Research MIRO M310) and the data were recorded at 2000 frames per second. The numerical calculations were performed with the Finite Volume Method (FVM) solving the three-dimensional Navier-Stokes equations for three phases: air and two selected immiscible fluids. The Volume of Fluid (VOF) technique was employed for modelling of the boundaries between the phases. Numerical modelling was done with the Finite Volume Method using an available OpenFOAM software. The experiment was based on three variables: • the height from which the drop of the selected fluids fell (the speed of the drop), • the thickness of the layers of the two selected immiscible fluids (a thin layer of the fluid with a lower density was spread over the higher-density fluid), • the size of the fluid droplet. The velocity and radius of the falling drop was calculated based on the recorded images. The used parameters allowed adequate projection of the impact of fluid droplets on a system of two immiscible liquids. Development of the numerical model of splash may further have practical applications in environmental protection (spraying of hazardous fluids, spread of fuels and other hazardous substances as a result of disasters, spraying (water cooling) of hot surfaces), and in agriculture (prevention of soil erosion). The study was partially funded from the National Science Centre (Poland) based on the decision no. DEC-2012/07/N/ST10/03280.

  3. Enabling two-phase microfluidic thermal transport systems using a novel thermal-flux degassing and fluid charging approach

    International Nuclear Information System (INIS)

    A novel two-port thermal-flux method has been proposed and demonstrated for degassing and charging two-phase microfluidic thermal transport systems with a degassed working fluid. In microscale heat pipes and loop heat pipes (mLHPs), small device volumes and large capillary forces associated with smaller feature sizes render conventional vacuum pump-based degassing methods quite impractical. Instead, we employ a thermally generated pressure differential to purge non-condensable gases from these devices before charging them with a degassed working fluid in a two-step process. Based on the results of preliminary experiments studying the effectiveness and reliability of three different high temperature-compatible device packaging approaches, an optimized compression packaging technique was developed to degas and charge a mLHP device using the thermal-flux method. An induction heating-based noninvasive hermetic sealing approach for permanently sealing the degassed and charged mLHP devices has also been proposed. To demonstrate the efficacy of this approach, induction heating experiments were performed to noninvasively seal 1 mm square silicon fill-hole samples with donut-shaped solder preforms. The results show that the minimum hole sealing induction heating time is heat flux limited and can be estimated using a lumped capacitance thermal model. However, further continued heating of the solder uncovers the hole due to surface tension-induced contact line dynamics of the molten solder. It was found that an optimum mass of the solder preform is required to ensure a wide enough induction-heating time window for successful sealing of a fill-hole. (paper)

  4. 酒石酸钾钠双水相体系分离纯化C-藻蓝蛋白%Separation and purification of C-phycocyanin using aqueous two-phase extraction technique of potassium sodium tartrate

    Institute of Scientific and Technical Information of China (English)

    赵丽; 彭一良; 康天; 蔡伟民

    2015-01-01

    采用廉价的聚乙二醇(PEG)/酒石酸钾钠建立双水相体系,从干螺旋藻中分离纯化藻蓝蛋白C-PC。以纯度(目的蛋白在620 nm处的特征吸光值和总蛋白在280 nm处吸光值的比值)为指标,优化体系参数。研究结果表明,体系pH 8.06,系线长为21.65%、体积比为0.22的PEG1000和酒石酸钾钠双水相体系分离纯化效果最好,纯度由0.42提高到1.27,高于食品级纯度0.7,纯化因子3.04,回收率85.11%。硫酸铵盐析提高粗提液纯度后,二次双水相纯度达到3.28,高于药品级3.0。得到的 C-PC具有较高的生物活性。%This paper used commercial aqueous two-phase system (ATPS) to efficiently extract and purify C-PC from the dryspirulina platensis. The purity of C-PC was defined as the relation between of 620 and 280 nm ab-sorbance, which was as the target to optimize the system parameters. The optimal conditions were proved in poly-ethylene glycol (PEG) 1000 and potassium sodium tartrate, system pH of 8.06, the tie-line length (TLL) of 21.65% (w/w) and the volume ratio (Vr) of 0.22 to increase the purity from the initial purity of 0.42 to 1.27 after the first extraction. The purity was over the food grade 0.7 and the purification factor was 3.04. The recovery yield was 85.11%. The purity was achieved up 3.28 after the saturation of ammonium sulfate in the second ATPS extraction. It was more than the pharmaceutical grade 3.0.

  5. Ultrasonic methodology measurement of two-phase (air-water) flows in cooling systems of nuclear reactor

    International Nuclear Information System (INIS)

    An ultrasonic methodology is proposed for the measurement for two phase (air-water) flow parameters. Ultrasonic backscattered signals were used to analyze the following parameters: average number of bubbles, interfacial area and void fraction. The results show a strong correlation between the parameters and the ultrasonic power signal obtained. (author)

  6. Proceedings of the CSNI Specialist Meeting on Transient Two-Phase Flow - Current Issues in System Thermal Hydraulics

    International Nuclear Information System (INIS)

    The 4. Specialists' Meeting on Transient Two Phase Flow was organized by the Safety Research Department of the French Nuclear Safety and Protection Institute at the request of the OECD Committee for the Safety of Nuclear Installations. After Toronto in 1976, Paris in 1978 and Pasadena in 1981, the Aix-en-Provence meeting was in keeping with the course of studies initiated by the Thermalhydraulic Systems Behavior Task Group of the Principal Working Group No.2 for discussing the achievements and defining the needs of safety research in accident thermal-hydraulics. 60 Specialists from 14 Countries (Belgium, Canada, Finland, France, Germany, Italy, Japan, the Netherlands, the United Kingdom, the USA, Spain, Sweden, Switzerland, Taiwan) attended the meeting, representing a large spectrum of experts from National Safety Authorities, Research Laboratories, Universities, Vendors and Utilities. These specialists had to review the 15-year research period which had elapsed since the last meetings. This period had been characterized by the issuance of the large thermalhydraulic computer codes for LWR accidents, the performance of several hundreds of separate effect tests for the development and the qualification of the physical models, the carrying-out of the large experimental programmes on system loops (up to scale 1) for verifying the computer codes. Although this research was mainly characterized by remarkable success, limitations still exist. In a safety approach, there need to be well identified and handled, and the specialists were asked to exchange their views in order to determine which solutions they expected to be affordable in the future. Safety applications have already started which use these latest research achievements. They raise specific problems such as the use of validation matrices, the evaluation of uncertainties, the identification and the control of unavoidable users' effects. The specialists were required to exchange their experience of applications

  7. Development of a Thermal Control System with Mechanically Pumped CO2 Two-Phase Loops for the AMS-02 Tracker on the ISS

    CERN Document Server

    Alberti, G; Ambrosi, G; Bardet, M; Battiston, R; Borsini, S; Cao, J F; Chen, Y; van Es, J; Gargiulo, C; Guo, K H; Guo, L; He, Z H; Huang, Z C; Koutsenko, V; Laudi, E; Lebedev, A; Lee, S C; Li, T X; Lin, Y L; Lv, S S; Menichelli, M; Miao, J Y; Mo, D C; Ni, J Q; Pauw, A; Qi, X M; Shue, G M; Sun, D J; Sun, X H; Tang, C P; Verlaat, B; Wang, Z X; Weng, Z L; Xiao, W J; Xu, N S; Yang, F K; Yeh, C C; Zhang, Z; Zwartbol, T

    2013-01-01

    To provide a stable thermal environment for the AMS-Tracker, a thermal control system based on mechanically pumped CO2 two-phase loops was developed. It has been operating reliably in space since May 19, 2011. In this article, we summarize the design, construction, tests, and performance of the AMS-Tracker thermal control system (AMS-TTCS).

  8. SDS/[C_nmim]Br/H_2O体系的双水相性质%Aqueous Two-Phase System(ATPS) Containing Ionic Liquids [C_nmim]Br and SDS

    Institute of Scientific and Technical Information of China (English)

    陈婷; 马爱青; 王菲; 尚亚卓; 刘洪来

    2012-01-01

    研究了咪唑类离子液体[Cnmim]Br与传统阴离子表面活性剂SDS混合水溶液的性质,结果显示混合水溶液性质随咪唑阳离子上烷烃链长的变化而呈现出明显的不同。当离子液体取代烷基链的碳数大于或等于6时,混合体系可以自发地分为共存的两相,即双水相。共存的两相界面清晰、性能稳定且能有效萃取染料二甲酚橙,有望成为新型高效的分离体系,在生物活性物质的纯化、分离中发挥作用。混合体系中离子液体和传统表面活性剂相对含量的改变引起混合溶液中表面活性剂聚集体尺寸和形态的变化,最终导致双水相上、下两相表观现象的差异。此外,离子液体、SDS头基间库仑力作用、烷烃链的疏溶剂力以及离子液体与SDS的协同效应,是形成溶致液晶的重要驱动力,导致较低浓度下十字花纹理层状液晶(LC)的生成。%Properties of mixed aqueous solutions of ionic liquid(Br) and traditional surfactant(SDS) were studied.Results showed that the properties of the mixed systems varied with the chain length of substituted alkyl in ionic liquids.Only those systems containing ionic liquids with equal to or more than 6 carbon atoms in alkyl chains can form aqueous two phase system(ATPS).The ATPS containing ionic liquids and surfactant has obvious extraction ability to xylenol orange and the potential to separate and purify biomaterials.The difference in appearance of ATPS should be attributed to the various size and shape of the surfactants aggregates formed in mixed solutions.Furthermore,the electrostatic attractive interaction,the hydrophobic interaction in addition to the synergistic effect between ionic liquids and SDS further promote the surfactant assembly,which leads to the formation of liquid crystal at lower surfactant concentration.

  9. Increased production of megakaryocytes near purity from cord blood CD34+ cells using a short two-phase culture system.

    Science.gov (United States)

    Boyer, Lucie; Robert, Amélie; Proulx, Chantal; Pineault, Nicolas

    2008-03-20

    Expansion of hematopoietic progenitor cells (HPC) ex vivo remains an important focus in fundamental and clinical research. The aim of this study was to determine whether the implementation of such expansion phase in a two-phase culture strategy prior to the induction of megakaryocyte (Mk) differentiation would increase the yield of Mks produced in cultures. Toward this end, we first characterized the functional properties of five cytokine cocktails to be tested in the expansion phase on the growth and differentiation kinetics of CD34+-enriched cells, and on their capacity to expand clonogenic progenitors in cultures. Three of these cocktails were chosen based on their reported ability to induce HPC expansion ex vivo, while the other two represented new cytokine combinations. These analyses revealed that none of the cocktails tested could prevent the differentiation of CD34+ cells and the rapid expansion of lineage-positive cells. Hence, we sought to determine the optimum length of time for the expansion phase that would lead to the best final Mk yields. Despite greater expansion of CD34+ cells and overall cell growth with a longer expansion phase, the optimal length for the expansion phase that provided greater Mk yield at near maximal purity was found to be 5 days. Under such settings, two functionally divergent cocktails were found to significantly increase the final yield of Mks. Surprisingly, these cocktails were either deprived of thrombopoietin or of stem cell factor, two cytokines known to favor megakaryopoiesis and HPC expansion, respectively. Based on these results, a short resource-efficient two-phase culture protocol for the production of Mks near purity (>95%) from human CD34+ CB cells has been established.

  10. Aqueous systems and geothermal energy

    International Nuclear Information System (INIS)

    Significant unpublished results reported include: osmotic coefficients of KCl solutions vs. molality at 109 to 2010C; cadmium ion diffusivities in CaCl2 hydrous melts; a x-ray diffraction study of the uranyl complex in water; solubility of amorphous silica in aqueous NaNO3 solutions at 100 to 3000C; and corrosion of carbon steel by geothermal brine

  11. Measurement and simulation of the turbulent dispersion of a radioactive tracer in a two-phase flow system

    Energy Technology Data Exchange (ETDEWEB)

    Hensel, F.; Rohde, U.

    1998-10-01

    The turbulent dispersion of a radiotracer in an experimental setup with a natural convection liquid-gaseous flow was investigated. A liquid-gaseous bubbly flow was generated in a narrow tank by injection of pressurized air into water or by catalytic disintegration of H{sub 2}O{sub 2}. Turbulent Prandtl numbers for gas and tracer dispersion were varied. In the case of higher gas superficial velocities (J{sub gas}{approx}5-15 mm/s), a reasonable agreement was achieved between calculated and measured tracer transport velocity and dispersion coefficient values. A nearly linear correlation between j{sub gas} and D was found in agreement with other authors. The calculation results contribute to a better understanding of the phenomena and interpretation of the measurement results as well as to the validation of the CFD code for turbulent two-phase flow applications. Further investigations are necessary to improve the agreement in the cases of H{sub 2}O{sub 2} disintegration and low gas superficial velocities. (orig.)

  12. Development of a fast neutron imaging system for investigating two-phase flows in nuclear thermal–hydraulic phenomena: A status report

    International Nuclear Information System (INIS)

    Highlights: • Development of a novel fast neutron imaging system for two-phase flows in fuel bundles. • Novel D–D fusion neutron generator with small emitting spot for imaging. • Dedicated fast neutron imaging detector based on plastic scintillator and SiPM. • Novel proton recoil converter coupled with THGEM readout as imaging detector. - Abstract: The present paper gives an overview of the status of an ongoing project aiming at the development of a fast neutron imaging system for investigating two-phase flows primarily in the context of nuclear fuel bundle development. Other potential subjects for investigations include steam explosions for severe accident research and liquid metal two-phase flows for Gen IV reactor systems. The project is carried out in the form of a feasibility study that should enable estimation of the ultimate imaging capabilities achievable. The imaging system used in the feasibility study consists of a compact, deuterium–deuterium fusion based neutron generator and dedicated imaging detectors. For the latter two promising concepts are developed in parallel: one is based on an array of plastic scintillators coupled with silicon photomultipliers, the other on a special multi-foil recoil proton converter coupled to a position sensitive charge readout using a micro pattern gas detector

  13. Study on constant-pressure specific heat of non-equi- librium phase change process in gas-liquid two-phase flow system

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In this paper, the air-water vapor-water system is taken as an example, and the formula of constantpressure specific heat during non-equilibrium phase change process in the two-phase flow system is deduced using the theory of two-phase flow and thermophysics. The constant-pressure specific heat of non-equilibrium phase change process is calculated with the corresponding numerical model, and the numerical results are compared to those of the equilibrium phase change process. It is shown that in evaporation process, the variational rate of the non-equilibrium specific heat increases with increasing initial fluid temperature and particle mass fraction. The smaller particle radius is, the faster the variational rate is. Meanwhile, the constant-pressure specific heat of equilibrium process is higher than that of the non-equilibrium process all the time.

  14. Metal separations using aqueous biphasic partitioning systems

    Energy Technology Data Exchange (ETDEWEB)

    Chaiko, D.J.; Zaslavsky, B.; Rollins, A.N.; Vojta, Y.; Gartelmann, J.; Mego, W. [Argonne National Lab., IL (United States). Chemical Technology Div.

    1996-05-01

    Aqueous biphasic extraction (ABE) processes offer the potential for low-cost, highly selective separations. This countercurrent extraction technique involves selective partitioning of either dissolved solutes or ultrafine particulates between two immiscible aqueous phases. The extraction systems that the authors have studied are generated by combining an aqueous salt solution with an aqueous polymer solution. They have examined a wide range of applications for ABE, including the treatment of solid and liquid nuclear wastes, decontamination of soils, and processing of mineral ores. They have also conducted fundamental studies of solution microstructure using small angle neutron scattering (SANS). In this report they review the physicochemical fundamentals of aqueous biphase formation and discuss the development and scaleup of ABE processes for environmental remediation.

  15. 乙醇-硫酸铵双水相萃取镉-碘化钾-罗丹明B离子缔合物%Extraction of cadmium-potassium iodide-rhodamine B ion association complex by alcohol-ammonium sulfate aqueous two-phase

    Institute of Scientific and Technical Information of China (English)

    曾云; 覃事栋; 姚康康; 王影; 肖苗

    2012-01-01

    In the presence of ammonium sulphate, the extraction behavior of Cd (Ⅱ) based on potassium iodide-Rhodamine B-alcohol system was studied and the optimal condition of phase separation was selected. Results showed that in the pH1 ~3 media, the extraction rate of [CdI4]2- by alcohol-ammonium sulfate aqueous two-phase system is only 35.5% , and the ion association complex, which is formed by adding rhodamine B, can be extracted completely by the aqueous two-phase system. In the system, Cd2+ can be dissociated completely from Zn2+, Fe3+, Co2+, Cu2+, and Ni2+.%研究了在( NH4) 2SO4存在下,碘化钾-罗丹明B-乙醇体系萃取Cd(Ⅱ)的行为及最佳分相条件.实验表明,在pH 1~3时,乙醇-( NH4 )2SO4双水相体系对[ CdI4]2-络阴离子的萃取率只有35.5%;加入罗丹明B后,该体系能完全萃取镉-碘化钾-罗丹明B形成的离子缔合物,而干扰离子Zn2+、Fe3+、Co2+、Cu2+、Ni2+不被萃取,实现Cd2+与上述离子的分离.

  16. Experimental and CFD-PBM approach coupled with a simplified dynamic analysis of mass transfer in phenol biodegradation in a three phase system of an aerated two-phase partitioning bioreactor for environmental applications

    Science.gov (United States)

    Moradkhani, Hamed; Anarjan Kouchehbagh, Navideh; Izadkhah, Mir-Shahabeddin

    2016-07-01

    A three-dimensional transient modeling of a two-phase partitioning bioreactor, combining system hydrodynamics, two simultaneous mass transfer and microorganism growth is modeled using computational fluid dynamics code FLUENT 6.2. The simulation is based on standard "k-ɛ" Reynolds-averaged Navier-Stokes model. Population balance model is implemented in order to describe gas bubble coalescence, breakage and species transport in the reaction medium and to predict oxygen volumetric mass transfer coefficient (kLa). Model results are verified against experimental data and show good agreement as 13 classes of bubble size is taking into account. Flow behavior in different operational conditions is studied. Almost at all impeller speeds and aeration intensities there were acceptable distributions of species caused by proper mixing. The magnitude of dissolved oxygen percentage in aqueous phase has a direct correlation with impeller speed and any increasing of the aeration magnitude leads to faster saturation in shorter periods of time.

  17. Production of dry Lactobacillus rhamnosus GG preparations by spray drying and lyophilization in aqueous two-phase systems

    OpenAIRE

    Katarzyna Leja; Radosław Dembczyński; Wojciech Białas; Tomasz Jankowski

    2009-01-01

    Background. Drying is the oldest method of food preservation. It works by removing water from the food, which prevents the growth of microorganisms and decay. Moreover, spray or freeze drying is also used for the preservation of probiotic cultures. The aim of this study was to compare a survival rate of probiotic bacteria Lactobacillus rhamnosus during spray and freeze drying in ATPS. These results were also compared with survival rate of cells dried under the same conditions but suspended on...

  18. Study on interaction between iron ( Ⅲ ) and pepsin in ionic liquid aqueous two-phase%离子液体双水相中铁(Ⅲ)与胃蛋白酶作用研究

    Institute of Scientific and Technical Information of China (English)

    王玉峰; 陈琳琳; 邓凡政

    2011-01-01

    The interaction between Fe3+ and the pepsin was investigated by fluorescence and UV absorption spectroscopy in ionic liquid aqueous two-phase. The results showed that the interactions,which resulted in the fluorescence quenching of pepsin, belonged to a static quenching mechanism. And by calculation the binding constants were 2. 56 × 105 L/mol (300 K) and 8. 91 × 104 L/mol (310 K) ,and the binding sites were 1. 21 (300 K) and 1. 14 (310 K) . The thermodynamic parameters showed that the in teraction between Fe3+ and pepsin was mainly driven by electrostatic force. Synchronous fluorescence spectrum was used to investigate the conformational change of pepsin.%运用荧光光谱和紫外光谱,研究了在离子液体双水相体系中铁(Ⅲ)与胃蛋白酶的相互作用.结果表明,Fe3+对胃蛋白酶产生了荧光猝灭作用,且属于静态猝灭过程.计算得到在300 K和310 K下的结合常数分别为2.56×105L/mol和8.91×104 L/mol,结合位点数分别为1.21和1.14.热力学参数表明,Fe3与胃蛋白酶之间的相互作用力类型为静电作用.用同步荧光法探讨了Fe3+对胃蛋白酶构象的影响.

  19. Interior Ballistics Two-Phase Reactive Flow Model Applied to Large Caliber Guided Projectile-Gun System

    OpenAIRE

    Mahmoud Rashad; XiaoBing Zhang; Hazem El Sadek

    2014-01-01

    Transient complex phenomena take place in a gun during interior ballistic cycle. Understanding these phenomena clearly and describing the mathematical models accurately are crucial to predict the behavior of gun system considering firing safety and performance. A mathematical model based on Eulerian-Eulerian approach for reactive gas-solid flow arising during interior ballistic cycle inside large caliber naval gun guided projectile system was developed. The model included the governing equati...

  20. Integrated extraction and purification of soy isoflavones by using aqueous micellar systems.

    Science.gov (United States)

    Cordisco, Estefanía; Haidar, Carla N; Coscueta, Ezequiel R; Nerli, Bibiana B; Malpiedi, Luciana P

    2016-12-15

    In this work, an integration of solid-liquid and liquid-liquid extractions by using aqueous micellar two-phase systems was evaluated as potential tool to purify soy isoflavones. Additionally, the proposed methodology aimed to preserve the protein content of the processed soy flour. The extractive assays were performed in AMTPS formed by Triton X-114 and sodium tartrate. In order to optimize the purification process, temperature and time were evaluated as independent variables. Under optimal working conditions, i.e. 100min and 33°C of incubation, IF were purified with a recovery percentage of 93 and a purification factor of almost 10. More importantly, the obtained sample presented an aglycone proportion superior to the reported by other methodologies. These results open perspectives to the use of aqueous micellar two-phase systems as an integrative methodology to extract, concentrate and purify isoflavones. PMID:27451211

  1. LITERATURE REVIEW: HEAT TRANSFER THROUGH TWO-PHASE INSULATION SYSTEMS CONSISTING OF POWDERS IN A CONTINUOUS GAS PHASE

    Science.gov (United States)

    The report, a review of the literature on heat flow through powders, was motivated by the use of fine powder systems to produce high thermal resistivities (thermal resistance per unit thickness). he term "superinsulations" has been used to describe this type of material, which ha...

  2. Determination of the archaeal and bacterial communities in two-phase and single-stage anaerobic systems by 454 pyrosequencing.

    Science.gov (United States)

    Maspolim, Yogananda; Zhou, Yan; Guo, Chenghong; Xiao, Keke; Ng, Wun Jern

    2015-10-01

    2-Phase anaerobic digestion (AD), where the acidogenic phase was operated at 2day hydraulic retention time (HRT) and the methanogenic phase at 10days HRT, had been evaluated to determine if it could provide higher organic reduction and methane production than the conventional single-stage AD (also operated at 12days HRT). 454 pyrosequencing was performed to determine and compare the microbial communities. The acidogenic reactor of the 2-phase system yielded a unique bacterial community of the lowest richness and diversity, while bacterial profiles of the methanogenic reactor closely followed the single-stage reactor. All reactors were predominated by hydrogenotrophic methanogens, mainly Methanolinea. Unusually, the acidogenic reactor contributed up to 24% of total methane production in the 2-phase system. This could be explained by the presence of Methanosarcina and Methanobrevibacter, and their activities could also help regulate reactor alkalinity during high loading conditions through carbon dioxide production. The enrichment of hydrolytic and acidogenic Porphyromonadaceae, Prevotellaceae, Ruminococcaceae and unclassified Bacteroidetes in the acidogenic reactor would have contributed to the improved sludge volatile solids degradation, and ultimately the overall 2-phase system's performance. Syntrophic acetogenic microorganisms were absent in the acidogenic reactor but present in the downstream methanogenic reactor, indicating the retention of various metabolic pathways also found in a single-stage system. The determination of key microorganisms further expands our understanding of the complex biological functions in AD process. PMID:26456614

  3. Performance of a passive emergency heat removal system of advanced reactors in two-phase flow and with high concentration of non-condensable

    International Nuclear Information System (INIS)

    The research and the development of passive emergency cooling systems are necessary for the new generation of thermo-nuclear systems. Some basic information on the operation of these systems require the research of some relative processes to the natural circulation, mainly in conditions of two-phase flow involving processes of condensation in the presence of non-condensable gases, because many found situations are new. The experimental facility called Bancada de Circulacao Natural (BCN) was used for the realization of tests with diverse concentrations of non-condensable and power levels. The non-condensable gas present in the circuit decreases the rate of heat transfer for the secondary of the heat exchanger, determining low efficiency of the heat exchanger. High concentration of non-condensable in the vapor condensation, determines negative pressure, and cause the inversion of the flow in the circuit. The initial concentration of non-condensable and the geometry of the circuit, in the inlet of the heat exchanger, determines the establishment of transitory with two-phase flow. The BCN was performed with the computational code of Analysis of Accidents and Thermal-Hydraulics RELAP5/MOD 3.3 and, the calculated values had been compared with the experimental data, presenting good agreement for small non-condensable concentrations. The values calculated for high concentrations of non-condensable had been satisfactory after the circuit to have reached the temperature of saturation in the electric heater. (author)

  4. The α +ɛ Two-Phase Equilibrium in the Fe-N-C System: Experimental Investigations and Thermodynamic Calculations

    Science.gov (United States)

    Göhring, Holger; Leineweber, Andreas; Mittemeijer, Eric Jan

    2016-09-01

    The present work is dedicated to investigating the occurrence of the α +ɛ equilibrium at temperatures typically applied for nitrocarburizing treatments. To this end, pearlitic Fe-C specimens were treated between 823 K and 863 K (550 °C and 590 °C) in gaseous nitriding and gaseous nitrocarburizing atmospheres, allowing control of the chemical potentials of N and C. Subsequently, the resulting compound-layer microstructures were investigated using light microscopy and X-ray diffraction. Thermodynamic calculations, adopting several models for the Fe-N-C system from the literature, were performed, showing significantly different predictions for both the sequence of the invariant reactions and their temperatures. Comparison of the experimental data and the theoretical calculations led to the conclusion that none of the models from the literature is able to realistically describe the experimentally observed constitution in the Fe-N-C system in the considered temperature range. Values/value ranges for the temperatures of the invariant reactions were obtained.

  5. Microstructure Formations in the Two-Phase Region of the Binary Peritectic Organic System TRIS-NPG

    Science.gov (United States)

    Mogeritsch, Johann; Ludwig, Andreas

    2012-01-01

    In order to prepare for an onboard experiment on the International Space Station (ISS), systematic directional solidification experiments with transparent hypoperitectic alloys were carried out at different solidification rates around the critical velocity for morphological stability of both solid phases. The investigations were done in the peritectic region of the binary transparent organic TRIS-NPG system where the formation of layered structures is expected to occur. The transparent appearance of the liquid and solid phase enables real time observations of the dynamic of pattern formation during solidification. The investigations show that frequently occurring nucleation events govern the peritectic solidification morphology which occurs at the limit of morphological stability. As a consequence, banded structures lead to coupled growth even if the lateral growth is much faster compared to the growth in pulling direction.

  6. Two-phase potential flow

    Science.gov (United States)

    Wallis, Graham B.

    1989-01-01

    Some features of two recent approaches of two-phase potential flow are presented. The first approach is based on a set of progressive examples that can be analyzed using common techniques, such as conservation laws, and taken together appear to lead in the direction of a general theory. The second approach is based on variational methods, a classical approach to conservative mechanical systems that has a respectable history of application to single phase flows. This latter approach, exemplified by several recent papers by Geurst, appears generally to be consistent with the former approach, at least in those cases for which it is possible to obtain comparable results. Each approach has a justifiable theoretical base and is self-consistent. Moreover, both approaches appear to give the right prediction for several well-defined situations.

  7. Thermal hydraulic analysis of two-phase closed thermosyphon cooling system for new cold neutron source moderator of Breazeale research reactor at Penn State

    Science.gov (United States)

    Habte, Melaku

    A cold neutron source cooling system is required for the Penn State's next generation cold neutron source facility that can accommodate a variable heat load up to about ˜10W with operating temperature of about 28K. An existing cold neutron source cooling system operating at the University of Texas Cold Neutron Source (TCNS) facility failed to accommodate heat loads upwards of 4W with the moderator temperature reaching a maximum of 44K, which is the critical temperature for the operating fluid neon. The cooling system that was used in the TCNS cooling system was a two-phase closed thermosyphon with a reservoir (TPCTR). The reservoir containing neon gas is kept at room temperature. In this study a detailed thermal analysis of the fundamental operating principles of a TPCTR were carried out. A detailed parametric study of the various geometric and thermo-physical factors that affect the limits of the operational capacity of the TPCTR investigated. A CFD analysis is carried out in order to further refine the heat transfer analysis and understand the flow structure inside the thermosyphon and the two-phase nucleate boiling in the evaporator section of the thermosyphon. In order to help the new design, a variety of ways of increasing the operating range and heat removal capacity of the TPCTR cooling system were analyzed so that it can accommodate the anticipated heat load of 10W or more. It is found, for example, that doubling the pressure of the system will increase the capacity index zeta by 50% for a system with an initial fill ratio FR of 1. A decrease in cryorefrigeration performance angle increases the capacity index. For example taking the current condition of the TCNS system and reducing the angle from the current value of ˜700 by half (˜350) will increase the cooling power 300%. Finally based on detailed analytic and CFD analysis the best operating condition were proposed.

  8. Corrosion inhibitor for aqueous ammonia absorption system

    Science.gov (United States)

    Phillips, Benjamin A.; Whitlow, Eugene P.

    1998-09-22

    A method of inhibiting corrosion and the formation of hydrogen and thus improving absorption in an ammonia/water absorption refrigeration, air conditioning or heat pump system by maintaining the hydroxyl ion concentration of the aqueous ammonia working fluid within a selected range under anaerobic conditions at temperatures up to 425.degree. F. This hydroxyl ion concentration is maintained by introducing to the aqueous ammonia working fluid an inhibitor in an amount effective to produce a hydroxyl ion concentration corresponding to a normality of the inhibitor relative to the water content ranging from about 0.015 N to about 0.2 N at 25.degree. C. Also, working fluids for inhibiting the corrosion of carbon steel and resulting hydrogen formation and improving absorption in an ammonia/water absorption system under anaerobic conditions at up to 425.degree. F. The working fluids may be aqueous solutions of ammonia and a strong base or aqueous solutions of ammonia, a strong base, and a specified buffer.

  9. The anaerobic co-digestion of fruit and vegetable waste and horse manure mixtures in a bench-scale, two-phase anaerobic digestion system.

    Science.gov (United States)

    Smith, David B; Almquist, Catherine B

    2014-01-01

    In this study, the anaerobic digestion of mixtures of food waste (FW) and horse manure was investigated using a bench-scale two-phase reactor system. Both phases were maintained at 35 degrees C for the duration of the 30-day study period. The first phase reactors were prepared with biomass mixtures in deionized water such that each mixture had an initial total solids (TS) concentration of 6 wt%. The second phase reactors were inoculated with cow manure in water two weeks prior to the study period at 3 wt% TS. The biogas from all second phase reactors contained greater than 60 vol% methane in the biogas before they were used in the study, thus indicating the presence of active methanogens. Filtrate (5 mL) from the first phase was used as feed to the second phase reactor. The chemical oxygen demand (COD), total organic carbon, and volatile solids (VS) of the feed from Phase 1 increased with FW content in the biomass mixture, and so the organic loading rates (OLRs) to the Phase 2 reactors also increased. Accordingly, the volume ofbiogas and methane generated from Phase 2 also increased with FW content. The low OLR (<0.2 g VS/L/day), the use of a two-phase system, and the use of filtrate from Phase las feed to Phase 2 allowed for high utilization of the feed; the observed specific methane yields (mL/g COD) were greater than 80% of the theoretical yields for all mixtures. The methane yields were statistically similar to within a 95% confidence interval.

  10. An ECT System Based on Improved RBF Network and Adaptive Wavelet Image Enhancement for Solid/Gas Two-phase Flow

    Institute of Scientific and Technical Information of China (English)

    陈夏; 胡红利; 张娟; 周屈兰

    2012-01-01

    Electrical capacitance tomography(ECT) is a non-invasive imaging technique that aims at visualizing the cross-sectional permittivity distribution and phase distribution of solid/gas two-phase flow based on the measured capacitance.To solve the nonlinear and ill-posed inverse problem:image reconstruction of ECT system,this paper proposed a new image reconstruction method based on improved radial basis function(RBF) neural network combined with adaptive wavelet image enhancement.Firstly,an improved RBF network was applied to establish the mapping model between the reconstruction image pixels and the capacitance values measured.Then,for better image quality,adaptive wavelet image enhancement technique was emphatically analyzed and studied,which belongs to a space-frequency analysis method and is suitable for image feature-enhanced.Through multi-level wavelet decomposition,edge points of the image produced from RBF network can be determined based on the neighborhood property of each sub-band;noise distribution in the space-frequency domain can be estimated based on statistical characteristics;after that a self-adaptive edge enhancement gain can be constructed.Finally,the image is reconstructed with adjusting wavelet coefficients.In this paper,a 12-electrode ECT system and a pneumatic conveying platform were built up to verify this image reconstruction algorithm.Experimental results demonstrated that adaptive wavelet image enhancement technique effectively implemented edge detection and image enhancement,and the improved RBF network and adaptive wavelet image enhancement hybrid algorithm greatly improved the quality of reconstructed image of solid/gas two-phase flow [pulverized coal(PC)/air].

  11. Transferência de massa em sistemas de aeração por jatos bifásicos Mass transfer in two-phase jet aeration systems

    Directory of Open Access Journals (Sweden)

    Iran Eduardo Lima Neto

    2013-03-01

    Full Text Available A injeção de misturas de ar e água na forma de jatos bifásicos é bastante usada para a aeração artificial em tanques e corpos hídricos. No presente trabalho, foram realizados experimentos para investigar a transferência de massa induzida por estes jatos em um tanque de aeração. Os resultados forneceram eficiências de transferência de oxigênio padrão variando entre aproximadamente 5 e 9%. Combinando-se os dados obtidos nesta pesquisa com os disponíveis na literatura, foram geradas correlações adimensionais para o coeficiente de transferência de massa em função da fração volumétrica de ar e do número de Froude densimétrico. Finalmente, os resultados foram aplicados a situações práticas envolvendo sistemas de aeração por jatos bifásicos.The injection of air-water mixtures through two-phase jets is widely used for artificial aeration in tanks and water bodies. In this study, experiments were conducted to investigate mass transfer induced by such jets in an aeration tank. The results provided standard oxygen transfer efficiencies ranging from about 5 to 9%. Combining the results obtained here with those from previous investigations allowed to generate dimensionless correlations for the mass transfer coefficient as a function of the gas volume fraction and the densimetric Froude number. Finally, the results were applied to practical situations involving two-phase jet aeration systems.

  12. 丙烯酰胺与季铵类阳离子单体双水相共聚的二次相分离%DOUBLE PHASE SEPARATION OF AQUEOUS TWO-PHASE COPOLYMERIZATION OF ACRYLAMIDE WITH QUATERNARY AMMONIUM CATIONIC MONOMERS

    Institute of Scientific and Technical Information of China (English)

    商宽祥; 单国荣

    2012-01-01

    以(2-甲基丙烯酰氧乙基)三甲基氯化铵(DMC)为例,用分光光度法研究了丙烯酰胺(AM)与季铵类阳离子单体在聚乙二醇(PEG)水溶液中双水相共聚的二次相分离.提出了二次相分离的机理,认为是阳离子单体单元的电离使得聚合物带上了正电荷,大分子间的静电排斥作用增加了其在PEG相中的溶解性(增容作用).讨论了反应条件对体系二次相分离的影响,发现二次相分离在一定的单体浓度和PEG浓度、以及适当的单体比例和PEG分子量条件下才能发生.总单体用量或PEG用量增加,第二次分相先出现后消失;PEG分子量增大,第二次分相逐渐明显;反应温度升高,两次分相更快完成.DMC摩尔分率为0.25~ 0.60时,第一次分相的临界转化率很小,第二次分相的临界转化率则随DMC摩尔分率的增加而增大;DMC摩尔分率超过0.60后,聚合反应主要在过渡区完成,第二次分相难以发生.%In the aqueous two-phase copolymerization of acrylamide ( AM ) with quaternary ammonium cationic monomers, such as 2-methylacryloylxyethyl trimethyl ammonium chloride (DMC),in aqueous poly-(ethylene glycol) (PEG) solution a double phase separation process was observed. In order to fix the critical points,the spectrophotometer was employed to detect the transmittance of the copolymerization system on-line. The transmittance curves showed three intervals. At the first interval, the transmittance keeps constant at the beginning,and then drops off quickly. At the second interval, the transmittance stops dropping and begins to increase. And at the last interval,the transmittance stops to keep constant for a moment,and then drops rapidly to nearly zero. When acrylamide was copolymerized with different monomers, the double phase separation process can be observed only for DMC and acryloylxyethyl trimethyl ammonium chloride ( DAC ) . It confirms that the double phase separation is attributed to the cationic nature of

  13. Two-phase flow model for energetic proton beam induced pressure waves in mercury target systems in the planned European Spallation Source

    International Nuclear Information System (INIS)

    Two-phase flow calculations are presented to investigate the thermo-hydraulic effects of the interaction between 2 ms long 1.3 GeV proton pulses with a closed mercury loop which can be considered as a model system of the target of the planned European Spallation Source (ESS) facility. The two-fluid model consists of six first-order partial differential equations that present one dimensional mass, momentum and energy balances for mercury vapor and liquid phases are capable to describe quick transients like cavitation effects or shock waves. The absorption of the proton beam is represented as instantaneous heat source in the energy balance equations. Densities and internal energies of the mercury liquid-vapor system is calculated from the van der Waals equation, but general method how to obtain such properties using arbitrary equation of state is also presented. A second order accurate high-resolution shock-capturing numerical scheme is applied with different kind of limiters in the numerical calculations. Our analysis shows that even 75 degree temperature heat shocks cannot cause considerable cavitation effects in mercury. (authors)

  14. Pressure Loss across Tube Bundles in Two-phase Flow

    Energy Technology Data Exchange (ETDEWEB)

    Sim, Woo Gun; Banzragch, Dagdan [Hannam Univ., Daejon (Korea, Republic of)

    2016-03-15

    An analytical model was developed by Sim to estimate the two-phase damping ratio for upward two-phase flow perpendicular to horizontal tube bundles. The parameters of two-phase flow, such as void fraction and pressure loss evaluated in the model, were calculated based on existing experimental formulations. However, it is necessary to implement a few improvements in the formulations for the case of tube bundles. For the purpose of the improved formulation, we need more information about the two-phase parameters, which can be found through experimental test. An experiment is performed with a typical normal square array of cylinders subjected to the two-phase flow of air-water in the tube bundles, to calculate the two-phase Euler number and the two-phase friction multiplier. The pitch-to-diameter ratio is 1.35 and the diameter of cylinder is 18mm. Pressure loss along the flow direction in the tube bundles is measured with a pressure transducer and data acquisition system to calculate the two-phase Euler number and the two-phase friction multiplier. The void fraction model by Feenstra et al. is used to estimate the void fraction of the two-phase flow in tube bundles. The experimental results of the two phase friction multiplier and two-phase Euler number for homogeneous and non-homogeneous two-phase flows are compared and evaluated against the analytical results given by Sim's model.

  15. Enhanced thermionic emission properties in textured two-phase LaB{sub 6}–BaB{sub 6} system prepared by spark plasma sintering

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Shen Lin, E-mail: shenlinz@sina.com [College of Mathematics and Physics, Jinggangshan University, Jian 343409 (China); Shanghai Key Laboratory of Special Artificial Microstructure and Pohl Institute of Solid State Physics and School of Physics Science and Engineering, Tongji University, Shanghai 200092 (China); State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing 100190 (China); Zhang, Jiu Xing, E-mail: zjiuxing@hfut.edu.cn [School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009 (China); Bao, Li Hong [Inner Mongolia Key Laboratory for Physics and Chemistry of Functional Materials, Inner Mongolia Normal University, Hohhot 010022 (China); Yu, Xiao Guang; Hu, Qiang Lin; Hu, Dong Qiang [College of Mathematics and Physics, Jinggangshan University, Jian 343409 (China)

    2014-10-25

    Graphical abstract: Room temperature XRD patterns of the nominal composition (La{sub 0.6}Ba{sub 0.4})B{sub 6} synthesized by SPS at 1400 °C for 5 min under 50 MPa. The XRD patterns reveal that the (La{sub 0.6}Ba{sub 0.4})B{sub 6} is a two-phase mixture of LaB{sub 6} and BaB{sub 6}. The inset is a macroscopic picture of the obtained (La{sub 0.6}Ba{sub 0.4})B{sub 6}. - Highlights: • (La{sub 0.6}Ba{sub 0.4})B{sub 6} has been successfully prepared by spark plasma sintering. • The obtained (La{sub 0.6}Ba{sub 0.4})B{sub 6} compound is a two-phase mixture of LaB{sub 6} and BaB{sub 6}. • The (0 0 1) texture is favorable for the decrease of work function. • The addition of BaB{sub 6} to LaB{sub 6} improves the electron emission performance. • (La{sub 0.6}Ba{sub 0.4})B{sub 6} is shown to be promising candidate for cathode applications. - Abstract: Structure, crystallographic orientation, and thermionic emission properties of the two-phase LaB{sub 6}–BaB{sub 6} system fabricated by a combined process of evaporation–condensation and spark plasma sintering (SPS) were investigated systematically. The powder X-ray diffraction (XRD) reveals that the obtained nominal composition (La{sub 0.6}Ba{sub 0.4})B{sub 6} compound exhibits coexistence of two isostructural phases of LaB{sub 6} and BaB{sub 6}. The electron backscatter diffraction (EBSD) confirms that the surface of the (La{sub 0.6}Ba{sub 0.4})B{sub 6} forms a clear (0 0 1) texture, which favors reduction in work function. Thermionic emission properties were measured in the temperature range between 1500 and 1873 K. The results indicated that the (La{sub 0.6}Ba{sub 0.4})B{sub 6} emitter displayed a low work function of 1.95 eV, and a high zero field emission current density of 10 A cm{sup −2} at 1773 K. Compared to the reported LaB{sub 6} and (La{sub 0.6}Sm{sub 0.4})B{sub 6} prepared for identical synthesis conditions, (La{sub 0.6}Ba{sub 0.4})B{sub 6} is shown to have the most excellent thermionic emission

  16. Gas-liquid two-phase severe slugging in a pipeline-riser system with S-shaped flexible riser: Experiments and modeling

    Science.gov (United States)

    Li, Nailiang; Guo, Liejin; Li, Wensheng

    2013-07-01

    The objective of the present work is to investigate the air-water two-phase flow patterns in pipeline-riser system with an S-shaped flexible riser. The test loop with 50 mm ID consists of a horizontal pipeline with 114 m in length, a downward inclined section with 16 m in length, and an S-shaped flexible riser with 24 m in height when downward section inclined at -2° with respective to the horizontal. The inclination angle of the downward section varied from -2° to -5°. The liquid superficial velocity ranged from 0.03 to 1.5 m/s, and the gas superficial velocity from 0.4 to 6.0 m/s. Identification and characterization of flow regimes were attained by pressure at riser-base and liquid holdup at riser top. Severe slugging I, severe slugging II, transition flow and stable flows are observed to exist. Flow pattern maps for each declination are presented and the transition criteria are proposed. It's found that as higher liquid and gas velocity is required for the transition of the flow in the pipeline from stratified to intermittent with increasing the declination angle, severe slugging was observed to occur over a wilder range of flow conditions. The effect of riser geometry and separator pressure on the occurrence of the flow patterns was also examined. It shows that the S-bend tends to suppress the initiation of severe slugging.

  17. Reconstruction of electrical capacitance tomography images based on fast linearized alternating direction method of multipliers for two-phase flow system

    Institute of Scientific and Technical Information of China (English)

    Chongkun Xia; Chengli Su⁎; Jiangtao Cao; Ping Li

    2016-01-01

    Electrical capacitance tomography (ECT) has been applied to two-phase flow measurement in recent years. Image reconstruction algorithms play an important role in the successful applications of ECT. To solve the il-posed and nonlinear inverse problem of ECT image reconstruction, a new ECT image reconstruction method based on fast lin-earized alternating direction method of multipliers (FLADMM) is proposed in this paper. On the basis of theoretical analysis of compressed sensing (CS), the data acquisition of ECT is regarded as a linear measurement process of permittivity distribution signal of pipe section. A new measurement matrix is designed and L1 regularization method is used to convert ECT inverse problem to a convex relaxation problem which contains prior knowledge. A new fast alternating direction method of multipliers which contained linearized idea is employed to minimize the objective function. Simulation data and experimental results indicate that compared with other methods, the quality and speed of reconstructed images are markedly improved. Also, the dynamic experimental results in-dicate that the proposed algorithm can fulfil the real-time requirement of ECT systems in the application.

  18. Extração no ponto nuvem de compostos orgânicos homólogos e isômeros Extraction of homologous and isomeric organic compounds by two-phase aqueous extraction

    Directory of Open Access Journals (Sweden)

    Lindemberg J. N. Duarte

    2005-06-01

    Full Text Available In this work, the feasibility of employing micelle-mediated extraction for selective separation of homologous or isomeric organic compounds is demonstrated. Firstly, the main parameters controlling extraction performances, such as surfactant concentration and temperature were varied. A Scheffé-type experimental design was demonstrated as a novel and useful method to characterize the various experimental factors. At each point selected in the two-phase domain and for a given solute, extraction percentage (E%, concentration ratio, phase volume ratio, and equilibrium partition coefficient (K C were determined. The values of E% and K C decrease in the following order: phenol > 1-phenylethanol ~ 2-phenylethanol > benzyl alcohol.

  19. Coupling two-phase fluid flow with two-phase darcy flow in anisotropic porous media

    KAUST Repository

    Chen, J.

    2014-06-03

    This paper reports a numerical study of coupling two-phase fluid flow in a free fluid region with two-phase Darcy flow in a homogeneous and anisotropic porous medium region. The model consists of coupled Cahn-Hilliard and Navier-Stokes equations in the free fluid region and the two-phase Darcy law in the anisotropic porous medium region. A Robin-Robin domain decomposition method is used for the coupled Navier-Stokes and Darcy system with the generalized Beavers-Joseph-Saffman condition on the interface between the free flow and the porous media regions. Obtained results have shown the anisotropic properties effect on the velocity and pressure of the two-phase flow. 2014 Jie Chen et al.

  20. A finite element code for modelling tracer transport in a non-isothermal two-phase flow system for CO2 geological storage characterization

    Science.gov (United States)

    Tong, F.; Niemi, A. P.; Yang, Z.; Fagerlund, F.; Licha, T.; Sauter, M.

    2011-12-01

    This paper presents a new finite element method (FEM) code for modeling tracer transport in a non-isothermal two-phase flow system. The main intended application is simulation of the movement of so-called novel tracers for the purpose of characterization of geologically stored CO2 and its phase partitioning and migration in deep saline formations. The governing equations are based on the conservation of mass and energy. Among the phenomena accounted for are liquid-phase flow, gas flow, heat transport and the movement of the novel tracers. The movement of tracers includes diffusion and the advection associated with the gas and liquid flow. The temperature, gas pressure, suction, concentration of tracer in liquid phase and concentration of tracer in gas phase are chosen as the five primary variables. Parameters such as the density, viscosity, thermal expansion coefficient are expressed in terms of the primary variables. The governing equations are discretized in space using the Galerkin finite element formulation, and are discretized in time by one-dimensional finite difference scheme. This leads to an ill-conditioned FEM equation that has many small entries along the diagonal of the non-symmetric coefficient matrix. In order to deal with the problem of non-symmetric ill-conditioned matrix equation, special techniques are introduced . Firstly, only nonzero elements of the matrix need to be stored. Secondly, it is avoided to directly solve the whole large matrix. Thirdly, a strategy has been used to keep the diversity of solution methods in the calculation process. Additionally, an efficient adaptive mesh technique is included in the code in order to track the wetting front. The code has been validated against several classical analytical solutions, and will be applied for simulating the CO2 injection experiment to be carried out at the Heletz site, Israel, as part of the EU FP7 project MUSTANG.

  1. Contrasted Fitness Costs of Docking and Antibacterial Constructs in the EE and EVida3 Strains Validates Two-Phase Anopheles gambiae Genetic Transformation System.

    Directory of Open Access Journals (Sweden)

    Doug Paton

    Full Text Available The deployment of transgenic mosquitoes carrying genes for refractoriness to malaria has long been seen as a futuristic scenario riddled with technical difficulties. The integration of anti-malarial effector genes and a gene-drive system into the mosquito genome without affecting mosquito fitness is recognized as critical to the success of this malaria control strategy. Here we conducted detailed fitness studies of two Anopheles gambiae s.s. transgenic lines recently developed using a two-phase targeted genetic transformation system. In replicated cage-invasion experiments, males and females of the EE Phase-1 docking strain and EVida3 Phase-2 strain loaded with an antimicrobial peptide (AMP expressed upon blood-feeding, were mixed with individuals of a recently-colonized strain of the Mopti chromosomal form. The experimental design enabled us to detect initial strain reproductive success differences, assortative mating and hybrid vigor that may characterize mosquito release situations. In addition, the potential fitness costs of the unloaded Phase-1 and loaded Phase-2 genetic constructs, independent of the strains' original genetic backgrounds, were estimated between the 1(st instar larvae, pupae and adult stages over 10 generations. The Phase-1 unloaded docking cassette was found to have significantly lower allelic fitness relative to the wild type allele during larval development. However, overall genotypic fitness was comparable to the wild type allele across all stages leading to stable equilibrium in all replicates. In contrast, the Phase-2 construct expressing EVida3 disappeared from all replicates within 10 generations due to lower fitness of hemi- and homozygous larvae, suggesting costly background AMP expression and/or of the DsRed2 marker. This is the first study to effectively partition independent fitness stage-specific determinants in unloaded and loaded transgenic strains of a Phase-1-2 transformation system. Critically, the high

  2. Contrasted Fitness Costs of Docking and Antibacterial Constructs in the EE and EVida3 Strains Validates Two-Phase Anopheles gambiae Genetic Transformation System.

    Science.gov (United States)

    Paton, Doug; Underhill, Anne; Meredith, Janet; Eggleston, Paul; Tripet, Frederic

    2013-01-01

    The deployment of transgenic mosquitoes carrying genes for refractoriness to malaria has long been seen as a futuristic scenario riddled with technical difficulties. The integration of anti-malarial effector genes and a gene-drive system into the mosquito genome without affecting mosquito fitness is recognized as critical to the success of this malaria control strategy. Here we conducted detailed fitness studies of two Anopheles gambiae s.s. transgenic lines recently developed using a two-phase targeted genetic transformation system. In replicated cage-invasion experiments, males and females of the EE Phase-1 docking strain and EVida3 Phase-2 strain loaded with an antimicrobial peptide (AMP) expressed upon blood-feeding, were mixed with individuals of a recently-colonized strain of the Mopti chromosomal form. The experimental design enabled us to detect initial strain reproductive success differences, assortative mating and hybrid vigor that may characterize mosquito release situations. In addition, the potential fitness costs of the unloaded Phase-1 and loaded Phase-2 genetic constructs, independent of the strains' original genetic backgrounds, were estimated between the 1(st) instar larvae, pupae and adult stages over 10 generations. The Phase-1 unloaded docking cassette was found to have significantly lower allelic fitness relative to the wild type allele during larval development. However, overall genotypic fitness was comparable to the wild type allele across all stages leading to stable equilibrium in all replicates. In contrast, the Phase-2 construct expressing EVida3 disappeared from all replicates within 10 generations due to lower fitness of hemi- and homozygous larvae, suggesting costly background AMP expression and/or of the DsRed2 marker. This is the first study to effectively partition independent fitness stage-specific determinants in unloaded and loaded transgenic strains of a Phase-1-2 transformation system. Critically, the high fitness of the

  3. Extraction of Phenylalanine Phase Systems Containing Enantiomers by Aqueous Two Combinatorial Chiral Selector

    Institute of Scientific and Technical Information of China (English)

    陈晓青; 刘莉; 焦飞鹏; 王珍

    2012-01-01

    In order to obtain a better enantioselectivity of phenylalanine enantiomers and establish the optimal chiral ex- traction conditions, the distribution behavior was investigated in aqueous two-phase systems which were composed of polyethylene glycol and ammonium sulfate containing combinatorial chiral selector: β-cyclodextrin and HP-β-cyclodextrin. The influence of the molar concentration ratio of combinatorial chiral selectors, the total molar concentration of combinatorial chiral selectors, pH value, buffer type and its concentration were thoroughly studied, respectively. The results show that the enantioselectivity reaches 1.53 under the optimal chiral extraction conditions This extraction is a potential economical and effective way for chiral resolution.

  4. Advanced Aqueous Separation Systems for Actinide Partitioning

    Energy Technology Data Exchange (ETDEWEB)

    Nash, Ken [Washington State Univ., Pullman, WA (United States); Martin, Leigh [Idaho National Lab. (INL), Idaho Falls, ID (United States); Lumetta, Gregg [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-04-02

    One of the most challenging aspects of advanced processing of used nuclear fuel is the separation of transplutonium actinides from fission product lanthanides. This separation is essential if actinide transmutation options are to be pursued in advanced fuel cycles, as lanthanides compete with actinides for neutrons in both thermal and fast reactors, thus limiting efficiency. The separation is difficult because the chemistry of Am3+ and Cm3+ is nearly identical to that of the trivalent lanthanides (Ln3+). The prior literature teaches that two approaches offer the greatest probability of devising a successful group separation process based on aqueous processes: 1) the application of complexing agents containing ligand donor atoms that are softer than oxygen (N, S, Cl-) or 2) changing the oxidation state of Am to the IV, V, or VI state to increase the essential differences between Am and lanthanide chemistry (an approach utilized in the PUREX process to selectively remove Pu4+ and UO22+ from fission products). The latter approach offers the additional benefit of enabling a separation of Am from Cm, as Cm(III) is resistant to oxidation and so can easily be made to follow the lanthanides. The fundamental limitations of these approaches are that 1) the soft(er) donor atoms that interact more strongly with actinide cations than lanthanides form substantially weaker bonds than oxygen atoms, thus necessitating modification of extraction conditions for adequate phase transfer efficiency, 2) soft donor reagents have been seen to suffer slow phase transfer kinetics and hydro-/radiolytic stability limitations and 3) the upper oxidation states of Am are all moderately strong oxidants, hence of only transient stability in media representative of conventional aqueous separations systems. There are examples in the literature of both approaches having been described. However, it is not clear at present that any extant process is sufficiently robust for application at the scale

  5. Pumped two-phase heat transfer loop

    Science.gov (United States)

    Edelstein, Fred

    1988-01-01

    A pumped loop two-phase heat transfer system, operating at a nearly constant temperature throughout, includes several independently operating grooved capillary heat exchanger plates supplied with working fluid through independent flow modulation valves connected to a liquid supply line, a vapor line for collecting vapor from the heat exchangers, a condenser between the vapor and the liquid lines, and a fluid circulating pump between the condenser and the heat exchangers.

  6. Time-resolved fast-neutron radiography of air-water two-phase flows in a rectangular channel by an improved detection system

    International Nuclear Information System (INIS)

    In a previous work, we have demonstrated the feasibility of high-frame-rate, fast-neutron radiography of generic air-water two-phase flows in a 1.5 cm thick, rectangular flow channel. The experiments have been carried out at the high-intensity, white-beam facility of the Physikalisch-Technische Bundesanstalt, Germany, using an multi-frame, time-resolved detector developed for fast neutron resonance radiography. The results were however not fully optimal and therefore we have decided to modify the detector and optimize it for the given application, which is described in the present work. Furthermore, we managed to improve the image post-processing methodology and the noise suppression. Using the tailored detector and the improved post-processing, significant increase in the image quality and an order of magnitude lower exposure times, down to 3.33 ms, have been achieved with minimized motion artifacts. Similar to the previous study, different two-phase flow regimes such as bubbly slug and churn flows have been examined. The enhanced imaging quality enables an improved prediction of two-phase flow parameters like the instantaneous volumetric gas fraction, bubble size, and bubble velocities. Instantaneous velocity fields around the gas enclosures can also be more robustly predicted using optical flow methods as previously

  7. Time-resolved fast-neutron radiography of air-water two-phase flows in a rectangular channel by an improved detection system

    Energy Technology Data Exchange (ETDEWEB)

    Zboray, Robert [Paul Scherrer Institute, PSI Villigen 5232 (Switzerland); Dangendorf, Volker; Bromberger, Benjamin; Tittelmeier, Kai [Physikalisch-Technische Bundesanstalt (PTB), Braunschweig 38116 (Germany); Mor, Ilan [Soreq NRC, Yavne 81800 (Israel)

    2015-07-15

    In a previous work, we have demonstrated the feasibility of high-frame-rate, fast-neutron radiography of generic air-water two-phase flows in a 1.5 cm thick, rectangular flow channel. The experiments have been carried out at the high-intensity, white-beam facility of the Physikalisch-Technische Bundesanstalt, Germany, using an multi-frame, time-resolved detector developed for fast neutron resonance radiography. The results were however not fully optimal and therefore we have decided to modify the detector and optimize it for the given application, which is described in the present work. Furthermore, we managed to improve the image post-processing methodology and the noise suppression. Using the tailored detector and the improved post-processing, significant increase in the image quality and an order of magnitude lower exposure times, down to 3.33 ms, have been achieved with minimized motion artifacts. Similar to the previous study, different two-phase flow regimes such as bubbly slug and churn flows have been examined. The enhanced imaging quality enables an improved prediction of two-phase flow parameters like the instantaneous volumetric gas fraction, bubble size, and bubble velocities. Instantaneous velocity fields around the gas enclosures can also be more robustly predicted using optical flow methods as previously.

  8. Time-resolved fast-neutron radiography of air-water two-phase flows in a rectangular channel by an improved detection system

    Science.gov (United States)

    Zboray, Robert; Dangendorf, Volker; Mor, Ilan; Bromberger, Benjamin; Tittelmeier, Kai

    2015-07-01

    In a previous work, we have demonstrated the feasibility of high-frame-rate, fast-neutron radiography of generic air-water two-phase flows in a 1.5 cm thick, rectangular flow channel. The experiments have been carried out at the high-intensity, white-beam facility of the Physikalisch-Technische Bundesanstalt, Germany, using an multi-frame, time-resolved detector developed for fast neutron resonance radiography. The results were however not fully optimal and therefore we have decided to modify the detector and optimize it for the given application, which is described in the present work. Furthermore, we managed to improve the image post-processing methodology and the noise suppression. Using the tailored detector and the improved post-processing, significant increase in the image quality and an order of magnitude lower exposure times, down to 3.33 ms, have been achieved with minimized motion artifacts. Similar to the previous study, different two-phase flow regimes such as bubbly slug and churn flows have been examined. The enhanced imaging quality enables an improved prediction of two-phase flow parameters like the instantaneous volumetric gas fraction, bubble size, and bubble velocities. Instantaneous velocity fields around the gas enclosures can also be more robustly predicted using optical flow methods as previously.

  9. Horseradish peroxidase/catalase-mediated cell-laden alginate-based hydrogel tube production in two-phase coaxial flow of aqueous solutions for filament-like tissues fabrication

    International Nuclear Information System (INIS)

    We report a method for preparing cell-laden hydrogel tubes. This method uses a coaxial double-orifice spinneret, simpler than triple-orifice spinnerets which have been used for preparing similar constructs. The intended application was to create a template for preparing filament-like structures composed of two heterogeneous living cell layers. An aqueous solution containing an alginate derivative possessing phenolic hydroxyl moieties (Alg-Ph), catalase and horseradish peroxidase (HRP) was extruded into an ambient flow of H2O2 aqueous solution. This operation enabled the Alg-Ph solution to be gellable through a HRP-catalyzed reaction, cross-linking the Ph moieties together. By altering flow rates of the Alg-Ph and H2O2 solutions along with the concentrations of catalase and H2O2, the diameter and membrane thickness of the hydrogel tubes were controllable between 250–550 µm and 70–140 µm, respectively. The viability of the HeLa cells enclosed in the hydrogel tubes with a diameter of 300 µm and a membrane thickness of 80 µm was 95.4%. Subsequently, the enclosed HeLa cells grew and filled the hollow core. A filament-like structure of HeLa cells covered with a layer of fibroblast 10T1/2 cells was obtained when confluency of fibroblast 10T1/2 cells was reached and the hydrogel matrix was degraded with alginate lyase. (paper)

  10. Two-phase viscoelastic jetting

    Energy Technology Data Exchange (ETDEWEB)

    Yu, J-D; Sakai, S.; Sethian, J.A.

    2008-12-10

    A coupled finite difference algorithm on rectangular grids is developed for viscoelastic ink ejection simulations. The ink is modeled by the Oldroyd-B viscoelastic fluid model. The coupled algorithm seamlessly incorporates several things: (1) a coupled level set-projection method for incompressible immiscible two-phase fluid flows; (2) a higher-order Godunov type algorithm for the convection terms in the momentum and level set equations; (3) a simple first-order upwind algorithm for the convection term in the viscoelastic stress equations; (4) central difference approximations for viscosity, surface tension, and upper-convected derivative terms; and (5) an equivalent circuit model to calculate the inflow pressure (or flow rate) from dynamic voltage.

  11. Results of the Workshop on Two-Phase Flow, Fluid Stability and Dynamics: Issues in Power, Propulsion, and Advanced Life Support Systems

    Science.gov (United States)

    McQuillen, John; Rame, Enrique; Kassemi, Mohammad; Singh, Bhim; Motil, Brian

    2003-01-01

    The Two-phase Flow, Fluid Stability and Dynamics Workshop was held on May 15, 2003 in Cleveland, Ohio to define a coherent scientific research plan and roadmap that addresses the multiphase fluid problems associated with NASA s technology development program. The workshop participants, from academia, industry and government, prioritized various multiphase issues and generated a research plan and roadmap to resolve them. This report presents a prioritization of the various multiphase flow and fluid stability phenomena related primarily to power, propulsion, fluid and thermal management and advanced life support; and a plan to address these issues in a logical and timely fashion using analysis, ground-based and space-flight experiments.

  12. Time-resolved fast-neutron radiography of air-water two-phase flows in a rectangular channel by an improved detection system

    OpenAIRE

    Zboray, Robert; Dangendorf, Volker; Mor, Ilan; Bromberger, Benjamin; Tittelmeier, Kai

    2015-01-01

    In a previous work we have demonstrated the feasibility of high-frame-rate, fast-neutron radiography of generic air-water two-phase flows in a 1.5 cm thick, rectangular flow channel. The experiments have been carried out at the high-intensity, white-beam facility of the Physikalisch-Technische Bundesanstalt, Germany, using an multi-frame, time-resolved detector developed for fast neutron resonance radiography. The results were however not fully optimal and therefore we have decided to modify ...

  13. Review of two-phase instabilities

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Han Ok; Seo, Han Ok; Kang, Hyung Suk; Cho, Bong Hyun; Lee, Doo Jeong

    1997-06-01

    KAERI is carrying out a development of the design for a new type of integral reactors. The once-through helical steam generator is important design features. The study on designs and operating conditions which prevent flow instability should precede the introduction of one-through steam generator. Experiments are currently scheduled to understand two-phase instability, evaluate the effect of each design parameter on the critical point, and determine proper inlet throttling for the prevention of instability. This report covers general two-phase instability with review of existing studies on this topics. The general classification of two phase flow instability and the characteristics of each type of instability are first described. Special attention is paid to BWR core flow instability and once-through steam generator instability. The reactivity feedback and the effect of system parameters are treated mainly for BWR. With relation to once-through steam generators, the characteristics of convective heating and dryout point oscillation are first investigated and then the existing experimental studies are summarized. Finally chapter summarized the proposed correlations for instability boundary conditions. (author). 231 refs., 5 tabs., 47 figs

  14. Time-resolved fast-neutron radiography of air-water two-phase flows in a rectangular channel by an improved detection system

    CERN Document Server

    Zboray, Robert; Mor, Ilan; Bromberger, Benjamin; Tittelmeier, Kai

    2015-01-01

    In a previous work we have demonstrated the feasibility of high-frame-rate, fast-neutron radiography of generic air-water two-phase flows in a 1.5 cm thick, rectangular flow channel. The experiments have been carried out at the high-intensity, white-beam facility of the Physikalisch-Technische Bundesanstalt, Germany, using an multi-frame, time-resolved detector developed for fast neutron resonance radiography. The results were however not fully optimal and therefore we have decided to modify the detector and optimize it for the given application, which is described in the present work. Furthermore, we managed to improve the image post-processing methodology and the noise suppression. Using the tailored detector and the improved post-processing significant increase in the image quality and an order of magnitude lower exposure times, down to 3.33 ms, have been achieved with minimized motion artifacts. Similar to the previous study, different two-phase flow regimes such as bubbly slug and churn flows have been e...

  15. Next steps in two-phase flow: executive summary

    Energy Technology Data Exchange (ETDEWEB)

    DiPippo, R.

    1980-09-01

    The executive summary includes the following topics of discussion: the state of affairs; the fundamental governing equations; the one-dimensional mixture model; the drift-flux model; the Denver Research Institute two-phase geothermal flow program; two-phase flow pattern transition criteria; a two-fluid model under development; the mixture model as applied to geothermal well flow; DRI downwell instrumentation; two-phase flow instrumentation; the Sperry Research Corporation downhole pump and gravity-head heat exchanger systems; and the Brown University two-phase flow experimental program. (MHR)

  16. Numerical method for two-phase flow discontinuity propagation calculation

    International Nuclear Information System (INIS)

    In this paper, we present a class of numerical shock-capturing schemes for hyperbolic systems of conservation laws modelling two-phase flow. First, we solve the Riemann problem for a two-phase flow with unequal velocities. Then, we construct two approximate Riemann solvers: an one intermediate-state Riemann solver and a generalized Roe's approximate Riemann solver. We give some numerical results for one-dimensional shock-tube problems and for a standard two-phase flow heat addition problem involving two-phase flow instabilities

  17. Pectinases partitioning in aqueous two-phase systems: an integration of the systems poly(ethylene glycol/crude dextran and poly(ethylene glycol/ammonium sulphate

    Directory of Open Access Journals (Sweden)

    NIKOLA VUKELIC

    2004-04-01

    Full Text Available The reaction of Pd(II with 1,8-dihydroxy-2-(pyrazol-5-ylazo-naphthalene-3-6-disulphonic acid (PACA sorbed onto Dowex 1-X8 ion-exchange resin was investigated with the aim of developing an absorption-spectrophotometric analytical method for the determination of low Pd(II concentrations in water. The immobilized reagent formed a 1:1 complex with Pd(II having an absorption maximum at 650 nm. Parameters, such as pH, wavelength and contact time were optimised for a given amount of the sorbed reagent. The linearity range of absorbance vs. Pd(II concentration extended from 5×10-6 – 5×10-5 M, 5×10-7 – 5×10-6 and 2.5×10-8 – 2.5×10-7 M when using 10, 100 and 200 ml of sample solution, respectively. With a 200 ml sample, the detection limit was 2.5×10-7 M Pd(II. Most metals, except Cu(II, did not interfere when present in up to 100 times the concentration of Pd(II.

  18. Interfacial Thermodynamics of Coexisting Aqueous Polymer Solutions

    NARCIS (Netherlands)

    Vis, M.

    2015-01-01

    Phase separation is commonly observed when two different polymers are present in aqueous solution, forming aqueous two-phase systems which typically consist for 90% of water. It is demonstrated that the presence of charge on one of the polymers results in an electric potential difference between the

  19. Two-phase flow dynamics in ECC

    International Nuclear Information System (INIS)

    The present report summarizes the achievements within the project ''Two-phase Systems and ECC''. The results during 1978 - 1980 are accounted for in brief as they have been documented in earlier reports. The results during the first half of 1981 are accounted for in greater detail. They contain a new model for the Basset force and test runs with this model using the test code RISQUE. Furthermore, test runs have been performed with TRAC-PD2 MOD 1. This code was implemented on Edwards Pipe Blowdown experiment (a standard test case) and UC-Berkeley Reflooding experiment (a non-standard test case.) (Auth.)

  20. Performance and microbial community dynamics in a two-phase anaerobic co-digestion system using cassava dregs and pig manure.

    Science.gov (United States)

    Ren, Jiwei; Yuan, Xufeng; Li, Jie; Ma, Xuguang; Zhao, Ye; Zhu, Wanbing; Wang, Xiaofen; Cui, Zongjun

    2014-03-01

    The two-phase anaerobic co-digestion of cassava dregs (CD) with pig manure (PM) was evaluated using four sequencing batch reactors (SBRs) and a continuously stirred tank reactor (CSTR). The effect of seven different PM to CD volatile solid ratios (10:0, 8:2, 6:4, 5:5, 4:6, 2:8 and 0:10) on the acidification phase was investigated. Results indicated the concentrations of soluble chemical oxygen demand, NH4-N and volatile fatty acids increased substantially at seven ratios. Co-acidification of PM and CD performed well. Methanogenic fermentation of the acidification products at seven ratios was steady in CSTR. The highest methane yield and VS removal of 0.352m(3)/kg VSadded and 68.5% were achieved at PM:CD (4:6). The microbial population in CSTR was analyzed using molecular methods. Findings revealed that bacteria such as Firmicutes and Bacteroidetes, archaea such as Methanobacteriales and Methanomicrobiales were advantageous populations. Co-digestion of PM and CD supported higher quantity and diversity of methanogens. PMID:24463413

  1. Two phase decision algorithm of replica allocation

    Institute of Scientific and Technical Information of China (English)

    Zuo Chaoshu; Liu Xinsong; Wang Zheng; Li Yi

    2006-01-01

    In distributed parallel server system, location and redundancy of replicas have great influence on availability and efficiency of the system. In order to improve availahility and efficiency of the system, two phase decision algorithm of replica allocation is proposed. The algorithm which makes use of auto-regression model dynamically predicts the future count of READ and WRITE operation, and then determines location and redundancy of replicas by considering availability, CPU and bands of the network. The algorithm can not only ensure the requirement of availability, but also reduce the system resources consumed by all the operations in a great scale. Analysis and test show that communication complexity and time complexity of the algorithm satisfy O( n ), resource optimizing scale increases with the increase of READ count.

  2. Thermo-Fluid Dynamics of Two-Phase Flow

    CERN Document Server

    Ishii, Mamrou

    2011-01-01

    "Thermo-fluid Dynamics of Two-Phase Flow, Second Edition" is focused on the fundamental physics of two-phase flow. The authors present the detailed theoretical foundation of multi-phase flow thermo-fluid dynamics as they apply to: Nuclear reactor transient and accident analysis; Energy systems; Power generation systems; Chemical reactors and process systems; Space propulsion; Transport processes. This edition features updates on two-phase flow formulation and constitutive equations and CFD simulation codes such as FLUENT and CFX, new coverage of the lift force model, which is of part

  3. Two Phase Flow Simulation Using Cellular Automata

    International Nuclear Information System (INIS)

    The classical mathematical treatment of two-phase flows is based on the average of the conservation equations for each phase.In this work, a complementary approach to the modeling of these systems based on statistical population balances of aut omata sets is presented.Automata are entities defined by mathematical states that change following iterative rules representing interactions with the neighborhood.A model of automata for two-phase flow simulation is presented.This model consists of fie lds of virtual spheres that change their volumes and move around a certain environment.The model is more general than the classical cellular automata in two respects: the grid of cellular automata is dismissed in favor of a trajectory generator, and the rules of interaction involve parameters representing the actual physical interactions between phases.Automata simulation was used to study unsolved two-phase flow problems involving high heat flux rates. One system described in this work consists of a vertical channel with saturated water at normal pressure heated from the lower surface.The heater causes water to boil and starts the bubble production.We used cellular automata to describe two-phase flows and the interaction with the heater.General rule s for such cellular automata representing bubbles moving in stagnant liquid were used, with special attention to correct modeling of different mechanisms of heat transfer.The results of the model were compared to previous experiments and correlations finding good agreement.One of the most important findings is the confirmation of Kutateladze's idea about a close relation between the start of critical heat flux and a change in the flow's topology.This was analyzed using a control volume located in the upper surface of the heater.A strong decrease in the interfacial surface just before the CHF start was encountered.The automata describe quite well some characteristic parameters such as the shape of the local void fraction in the

  4. Surfactant-coated Candida rugosa Lipase as Catalyst for Hydrolysis of Olive Oil in Solvent-Free Two-Phase System%表面活性剂包衣Candida rugosa脂肪酶在无溶剂下油水两相体系中催化橄榄油水解

    Institute of Scientific and Technical Information of China (English)

    宋宝东; 丁辉; 吴金川; Hayashi Y; Talukder MMR; 王世昌

    2003-01-01

    The surfactant-coated Candida rugosa lipase was used as catalyst for hydrolysis of olive oil in two-phase system consisting of olive oil and phosphate buffer without organic solvent. For both the coated and native lipases,the optimal buffer/oil volume ratio of 1.0, aqueous pH 6.8 and reaction temperature 30℃ were determined. The maximum activity of the coated lipase was ca 1.3 times than that of the native lipase. The half-life of the coated lipase in olive oil and the native lipase in phosphate buffer was ca 9 h and 12 h, and the final residual activity was 27% and 20% of their initial values, respectively. The final substrate conversion by the coated lipase was ca 20% higher than that of the native lipase.

  5. Measurement and Correlation of the Phase Diagram Data for 1-Ethyl-3-methylimidazolium Dimethyl phosphate+K3PO4/ K2HPOjK2CO3+ H20 Ionic Liquids Aqueous Two-Phase Systems at T-- 298.15 K%1-乙基-3-甲基咪唑磷酸二甲酯盐+K3P04/K2HP04/K2C03+H20离子液体双水相体系在T=298.15K时相图数据的测量和相关性

    Institute of Scientific and Technical Information of China (English)

    王良; 朱红; 闫永胜

    2012-01-01

    实验测定了1-乙基-3.甲基咪唑磷酸二甲酯盐(1-ethyl-3-methylimidazolium dimehtyl phosphate, [Emim]DMP )+盐(K3P04,K2HP04和K2C03)+H20体系在298.15K的双节点数据.用3个经验方程与双节点数据关联,发现Merchuk方程简便并且准确性好.不同盐的分相能力顺序为K3P04〉K2HP04〉K2C03,这与水合离子Gibbs自由能(△hydG)有关.用Othmer.Tobias方程、Bancroft方程和二元参数方程计算此方法和相应系线数据的可靠性.[Emim]DMP是常见的离子液体,广泛用于萃取石油燃料中的硫.报道T[Emim]DMP+盐+H20体系的相图数据.%Binodal data for the 1-ethyl-3-methylimidazolium dimethyl phosphate ([Emim]DMP)+salt (K3PO4, K2HPO4, and K2CO3)q-H20 systems were experimentally determined at 298.15 K. Three empirical equations were used to correlate binodal data. The Merchuk equation is an uncomplicated one for fine accu racy. The ability of different salts studied for phase separation are in the order of K3PO4 〉 K2HPO4 〉 K2CO3, which may be related to the Gibbs free energy of hydration of the ions (AhydG). The reliability of the calcula tion method and the corresponding tie-line data was described by the Othmer-Tobias equation and Bancroft equation, as well as the twoparameter equation. [Emim]DMP is a familiar ionic liquid, which is extensively used for extractive desulfurization of fuel oils. This is the first time to report the data for phase diagrams of [Emim]DMP 4- salt + water systems.

  6. Critical transport velocity in two-phase, horizontal pipe flow

    Energy Technology Data Exchange (ETDEWEB)

    Sommerville, D. (U.S. Army Chemical Research, Development and Engineering Center, Aberdeen Proving Grounds, MD (US))

    1991-02-01

    This paper reports on the suspension of solid particles or entrainment of liquid droplets in two- phase flow. Theoretical and empirical relationships have been derived for both instances without any consideration to the similarities between the two. However, a general relation for two-phase flow is desirable since there are systems that cannot be readily defined due to the dual (solid/liquid) nature of the transported material, such as colloids, pulp, slurries, and sludge. Using turbulence theory, one general equation can be derived to predict critical transport velocities for two-phase horizontal flow.

  7. Modeling of two-phase slug flow

    International Nuclear Information System (INIS)

    When gas and liquid flow in a pipe, over a range of flow rates, a flow pattern results in which sequences of long bubbles, almost filling the pipe cross section, are successively followed by liquid slugs that may contain small bubbles. This flow pattern, usually called slug flow, is encountered in numerous practical situations, such as in the production of hydrocarbons in wells and their transportation in pipelines; the production of steam and water in geothermal power plants; the boiling and condensation in liquid-vapor systems of thermal power plants; emergency core cooling of nuclear reactors; heat and mass transfer between gas and liquid in chemical reactors. This paper provides a review of two phase slug flow modeling

  8. Control System of Two-Phase Brushless DC Gyro Motor Based on DSP%基于DSP的两相无刷直流陀螺电机稳速系统

    Institute of Scientific and Technical Information of China (English)

    吴梅锡; 付鲁华; 林玉池

    2013-01-01

    The research of the influence of gyro motor speed stability on the north-finding result is studied in order to improve the gyro north-finding precision. The paper introduces a two-phase brushless DC gyro motor control system based on TMS320LF2407A. First,it expounds the two-phase brushless DC motor's working principle. Then through the design of the hardware and software system, the close-loop control of two-phase brushless DC gyro motor is realized. The experimental results show that,the system can drive the brushless DC gyro motor well starting,braking and smooth running. The precision of the steady speed is less than 10~6 and the characteristics of the system satisfy the gyroscope demand.%为了进一步提高陀螺仪的寻北精度,分析研究了陀螺电机转速大小和转速精度对寻北结果的影响.在此基础上设计了一种基于TMS320LF2407A的两相无刷直流陀螺电机控制系统,阐述了两相无刷直流电机的工作原理,给出了电机的简化结构及数学模型,并通过对硬件系统和软件算法的设计实现了两相无刷直流陀螺电机的闭环控制.实验结果表明:系统可以很好地完成电机的启动、制动和平稳运行,转速精度优于10-6,满足陀螺仪的工作要求.

  9. 基于AT89C52单片机的步进电机控制系统研究%Research of Control System of Two-phase Hybrid Stepping Motor Based on AT89C52 Microcontrollers

    Institute of Scientific and Technical Information of China (English)

    何冲; 王淑红; 侯胜伟; 牛慧文

    2012-01-01

    The design scheme Based on AT89C52 Microcontrollers of two phase hybrid stepping motor control system is introduced, reflects two phase hybrid stepping motor control method in principle, increase the flexibility of stepping motor control system design. The control system adopts AT89C52 as controller, use BUW49 power tube of double H bridge type circuit as driver, join button control and LCD1602 display. The circuit structure of control system is simple and the thinking design is clearly. Experimental results shows that the control system operation is simple and reliable, it has strong practicability.%本文介绍了基于AT89C52单片机的两相混合式步进电机控制系统的设计方案,增加了步进电机控制系统设计的灵活性。控制系统采用AT89C52单片机作为控制器,由达林顿功率管BUW49组成的双H桥式电路作为驱动器,加入按键控制及LCD1602显示。控制系统的电路结构简单、设计思路清晰。实验表明,控制系统操作简单、运行可靠,具有较强的实用性。

  10. Aspects of two-phase gas--liquid flow

    International Nuclear Information System (INIS)

    A wide range of topics related to current research on liquid-gas flow is reviewed, and the relevance of these topics to the design of heat exchangers is discussed. Information is included on flow patterns; system variables; mathematical models for parallel flow and non-parallel flow; critical two-phase flow; unsteady flow; and types of two-phase flow equipment used in industry. (U.S.)

  11. Two-phase cooling fluids; Les fluides frigoporteurs diphasiques

    Energy Technology Data Exchange (ETDEWEB)

    Lallemand, A. [Institut National des Sciences Appliquees (INSA), 69 - Lyon (France)

    1997-12-31

    In the framework of the diminution of heat transfer fluid consumption, the concept of indirect refrigerating circuits, using cooling intermediate fluids, is reviewed and the fluids that are currently used in these systems are described. Two-phase cooling fluids advantages over single-phase fluids are presented with their thermophysical characteristics: solid fraction, two-phase mixture enthalpy, thermal and rheological properties, determination of heat and mass transfer characteristics, and cold storage through ice slurry

  12. Protons and Hydroxide Ions in Aqueous Systems.

    Science.gov (United States)

    Agmon, Noam; Bakker, Huib J; Campen, R Kramer; Henchman, Richard H; Pohl, Peter; Roke, Sylvie; Thämer, Martin; Hassanali, Ali

    2016-07-13

    Understanding the structure and dynamics of water's constituent ions, proton and hydroxide, has been a subject of numerous experimental and theoretical studies over the last century. Besides their obvious importance in acid-base chemistry, these ions play an important role in numerous applications ranging from enzyme catalysis to environmental chemistry. Despite a long history of research, many fundamental issues regarding their properties continue to be an active area of research. Here, we provide a review of the experimental and theoretical advances made in the last several decades in understanding the structure, dynamics, and transport of the proton and hydroxide ions in different aqueous environments, ranging from water clusters to the bulk liquid and its interfaces with hydrophobic surfaces. The propensity of these ions to accumulate at hydrophobic surfaces has been a subject of intense debate, and we highlight the open issues and challenges in this area. Biological applications reviewed include proton transport along the hydration layer of various membranes and through channel proteins, problems that are at the core of cellular bioenergetics. PMID:27314430

  13. Use of hydrophilic ionic liquids in a two-phase system to improve Mung bean epoxide hydrolases-mediated asymmetric hydrolysis of styrene oxide.

    Science.gov (United States)

    Chen, Wen-Jing; Lou, Wen-Yong; Yu, Chun-Yang; Wu, Hong; Zong, Min-Hua; Smith, Thomas J

    2012-12-31

    A comparative study was made of Mung bean epoxide hydrolases-catalyzed asymmetric hydrolysis of styrene oxide to (R)-1-phenyl-1,2-ethanediol in an n-hexane/buffer biphasic system containing various hydrophilic ionic liquids (ILs). Compared to the n-hexane/buffer biphasic system alone, addition of a small amount of hydrophilic ILs reduced the amount of non-enzymatic hydrolysis, and improved the reaction rate by up to 22%. The ILs with cation containing an alkanol group, namely [C(2)OHMIM][BF(4)] and [C(2)OHMIM][TfO], and the choline amino acid ILs [Ch][Arg] and [Ch][Pro] were found to be the most suitable co-solvents for the reaction, owing to their good biocompatibility with the enzyme, which led to high initial rates (0.99-1.25 μmol/min) and high product e.e.s (95%). When substrate concentration was around 30 mM, where optimal performance was observed with the IL-containing systems, the product e.e. was improved from 90% without ILs to ≥95% in the presence of ILs.

  14. Review on two-phase flow instabilities in narrow spaces

    International Nuclear Information System (INIS)

    Instabilities in two-phase flow have been studied since the 1950s. These phenomena may appear in power generation and heat transfer systems where two-phase flow is involved. Because of thermal management in small size systems, micro-fluidics plays an important role. Typical processes must be considered when the channel hydraulic diameter becomes very small. In this paper, a brief review of two-phase flow instabilities encountered in channels having hydraulic diameters greater than 10 mm are presented. The main instability types are discussed according to the existing experimental results and models. The second part of the paper examines two-phase flow instabilities in narrow spaces. Pool and flow boiling cases are considered. Experiments as well as theoretical models existing in the literature are examined. It was found that several experimental works evidenced these instabilities meanwhile only limited theoretical developments exist in the literature. In the last part of the paper an interpretation of the two-phase flow instabilities linked to narrow spaces are presented. This approach is based on characteristic time scales of the two-phase flow and bubble growth in the capillaries

  15. Two-phases-service queuing system with server breakdown and vacations%带有服务台故障和两阶段服务的休假排队系统

    Institute of Scientific and Technical Information of China (English)

    曾慧; 岳德权

    2011-01-01

    为了解决现实生产生活中的具有两阶段服务性质的休假排队问题,利用马尔可夫过程理论建立系统稳态概率方程组,并利用分块矩阵解法,得到了稳态概率的矩阵解.由此得出系统的平均队长、平均等待队长等性能指标.该成果对解决两阶段服务排队模型具有重要的理论意义和应用价值.%In order to solve the vacation queue problems with a two-phase of service in real-life production, the equations of steady-state probability were derived by applying the Markov process theory in this study. Subsequently, the matrix form solution of steady-state probability was found by using block matrix method. Furthermore, some performance measures of the system, such as the expected number of customers in the system and the expected number of customers in the queue, were also obtained. The study on the queuing systems with two-phase of service is of theoretical significance and application value.

  16. Two-phase flow simulation inside a tubing string with artificial lift system PCP based; Simulacao do escoamento bifasico em uma coluna de producao com sistema de elevacao artificial por BCP

    Energy Technology Data Exchange (ETDEWEB)

    Vidal, F.J.T.; Salazar, A.O.; Maitelli, A.L. [Rio Grande do Norte Univ., Natal, RN (Brazil). Programa de Pos-graduacao em Engenharia Eletrica]. E-mail: francisco@dca.ufrn.br; andres@dca.ufrn.br; maitelli@dca.ufrn.br; Assmann, B.W. [PETROBRAS S.A., Natal/Fortaleza, RN/CE (Brazil). Unidade de Negocios]. E-mail: benno@petrobras.com.br; Lima, J.A. [Rio Grande do Norte Univ., Natal, RN (Brazil). Dept. de Engenharia Mecanica. Programa de Pos-graduacao em Engenharia Mecanica]. E-mail: jalima@dem.ufrn.br

    2005-07-01

    The main goal of the present work is the computational simulation of the vertical two-phase flow within a tubing string in the production of oil equipped with a PCP artificial lift system (Progressive Cavity Pumping). By initially adopting the homogeneous model for the two-phase mixture (oil and gas), the fields of velocity and pressure are evaluated for prediction of pressure loss along the tubing, as well as the spatial and temporal behavior of typical parameters as gas-oil ratio, bubble pressure, solubility ratio, void fraction, gas and oil formation volume factors, among others. Prediction of these properties is an integral part of pressure loss calculations, as well as they constitute essential parameters for optimization of any artificial lift system. The numerical simulation is based on the transport equations (continuity and momentum equations) for a pseudo-fluid through the finite difference method, and the mixture properties are evaluated by employing the black-oil fluid model. Behavior analyses of the main flow variables are made and results for a typical artificial lift system PCP based are discussed. (author)

  17. Advances in two-phase flow instrumentation

    International Nuclear Information System (INIS)

    Multiphase flow measurements have become increasingly in a number of process and power systems. However, the need to predict system behavior under transient and accident conditions in nuclear reactors has given impetus to research in this area. Since moving internal interfaces make theoretical predictions difficult, much information for design and supporting analyses is based on experimental observation. The simplest models involving parameters representing mixture density and mixture mass flux, assume thermal equillibrium of the two phases, and are applicable only to a limited number of situations. Most of the parameters, such as interface area and local mixture density, needed for more sophisticated models, are particularly difficult to measure. At present, there are no truly direct methods for measuring local void fraction or mass flux. Local measurements can be taken for a cross-section using, for example, a system of simultaneously quick-closing valves. These valves obtained for the cross section can be integrated, and the result compared with direct measurements for an entire pipeline. Consistent results tend to support the response-model used

  18. Computer simulation model for coupled grain growth and Ostwald ripening -- Application to Al2O3-ZrO2 two-phase systems

    International Nuclear Information System (INIS)

    A kinetic model based on generalized continuum time-dependent Ginzburg-Landau (TDGL) equations is proposed for studying coupled grain growth and Ostwald ripening in multiphase systems. In this model, an arbitrary multiphase microstructure is described by many orientation field variables which represent crystallographic orientations of grains in each phase and by n - 1 composition field variables which distinguish the compositional differences among n phases. Microstructural development during simultaneous grain growth and Ostwald ripening is predicted by the temporal evolution of these field variables by numerically solving the TDGL equations. A particular example, Al2O3-ZrO2 particulate composite, was considered. The effects of the volume fraction of ZrO2 on the microstructural features and their evolution were studied and compared to experimental observations and previous thermodynamic analysis

  19. Isotope effect of potassium in an aqueous/amalgam system

    International Nuclear Information System (INIS)

    The isotope fractionation of potassium in an aqueous (KOH)/amalgam system has been studied. Two types of isotope effects with opposite isotope enrichment directions were observed in the electrolysis of potassium from the aqueous into the amalgam phase under constant electrolytic potentials. It was found that the first isotope effect causing the light isotope enriched in the amalgam is related to the kinetic process of the mass transfer through the aqueous/amalgam interface, while the second one leading to the enrichment of the heavy isotope in the amalgam phase is produced by the isotope-exchange equilibrium. The temperature dependence of the equilibrium isotope effect was also investigated using single-stage and multi-stage techniques. It was observed that the equilibrium isotope effect increases as the temperature increases in the range of 293-371 K. An empirical equation was used to fit the variations of the isotope effects with temperature for potassium together with the other alkaline and alkaline earth metals studied in the same system. The origin of the equilibrium isotope fractionation in the electron-exchange system was discussed. Furthermore, the mass dependence of the separation coefficients of the alkaline and alkaline earth metals observed in aqueous/amalgam and ion-exchange systems were compared. At 293 K the equilibrium isotope separation coefficient for the 39K/41K isotopes in the amalgam system was determined as (5.6 ± 0.6).10-3. (author)

  20. Tracer Partitioning in Two-Phase Flow

    Science.gov (United States)

    Sathaye, K.; Hesse, M. A.

    2012-12-01

    The concentration distributions of geochemical tracers in a subsurface reservoir can be used as an indication of the reservoir flow paths and constituent fluid origin. In this case, we are motivated by the origin of marked geochemical gradients in the Bravo Dome natural CO2 reservoir in northeastern New Mexico. This reservoir contains 99% CO2 with various trace noble gas components and overlies the formation brine in a sloping aquifer. It is thought that magmatic CO2 entered the reservoir, and displaced the brine. This displacement created gradients in the concentrations of the noble gases. Two models to explain noble gas partitioning in two-phase flow are presented here. The first model assumes that the noble gases act as tracers and uses a first order non-linear partial differential equation to compute the volume fraction of each phase along the displament path. A one-way coupled partial differential equation determines the tracer concentration, which has no effect on the overall flow or phase saturations. The second model treats each noble gas as a regular component resulting in a three-component, two-phase system. As the noble gas injection concentration goes to zero, we see the three-component system behave like the one-way coupled system of the first model. Both the analytical and numerical solutions are presented for these models. For the process of a gas displacing a liquid, we see that a noble gas tracer with greater preference for the gas phase, such as Helium, will move more quickly along the flowpath than a heavier tracer that will more easily enter the liquid phase, such as Argon. When we include partial miscibility of both the major and trace components, these differences in speed are shown in a bank of the tracer at the saturation front. In the three component model, the noble gas bank has finite width and concentration. In the limit where the noble gas is treated as a tracer, the width of the bank is zero and the concentration increases linearly

  1. Biogasification of steam-exploded wheat straw by a two-phased digestion system%汽爆麦草的两相法生物气化

    Institute of Scientific and Technical Information of China (English)

    陈洪章; 王麾; 张爱军; 李佐虎

    2005-01-01

    蒸汽爆破作为一种新型的预处理方法被初次运用于麦草的两相气化系统,以碳酸氢铵作为补充氮源调节碳氮比,并在相同条件下以未汽爆麦草作对照试验.以汽爆麦草为原料时,水解反应器的pH值低于加入未汽爆麦草的pH值,并且在25 d后慢慢升至7;以两种麦草为原料时,甲烷反应器的pH都稳定在7左右,此时最适合甲烷生成.汽爆麦草的总固形物和挥发性固形物含量分别降低了57.5%和62.1%,下降率差不多是未汽爆麦草的2倍;纤维素和半纤维素的降解率也有了显著的提高,分别为63.0%和67.4%;木质素的降解率变化不大,都在5%左右.汽爆麦草的总产气量高于非汽爆麦草,并且一直保持较高的增长率,而非汽爆麦草的增长率一直较低;两种麦草产生的生物气中的甲烷含量大致相同,在水解反应器中后期为50%左右,在甲烷反应器中为70%左右.以上结果表明,汽爆可以促进麦草的降解,提高生物气的产量,是一种行之有效的预处理技术.%In the study, steam-explosion, a novel pretreatment method of substrate, was firstly introduced in the twophased digestion system. Ammonium bicarbonate was used as added nitrogen source to adjust C/N in the system. Under the same conditions, experiments using NPWS (non-pretreated wheat straw) were processed as the control. Results showed that pH value in the hydrolysis reactor using SEWS (Steam-exploded wheat straw) was lower and increased slowly to 7 in 25 days. In methanogenesis reactors using SEWS and NPWS, pH value was all around 7, which is most suitable to produce methane. In the digestion system using SEWS, the content of TS (Total solid) and VS (Volatile solid) decreased by 57.5% and by 62.1%, respectively, about twice as high as NWPS. The degradation rate of cellulose and semi-cellulose of SEWS were 63.0% and 67.4%, respectively, much higher than NPWS. The degradation rate of the lignin is similar and about 5 %. The total

  2. Ecoulements diphasiques instables dans les systèmes pipeline/riser Unsteady Two-Phase Flows in Pipeline/Riser Systems

    Directory of Open Access Journals (Sweden)

    Fabre J.

    2006-11-01

    Full Text Available Les instabilités hydrodynamiques de l'écoulement dans les systèmes pipeline/riser ont été étudiées sur une boucle d'essais en tubes transparents de diamètre intérieur 0,053 m, longueur 25 m pour la partie pipeline et 13,5 m pour la partie riser. Les expériences effectuées sur de l'eau et de l'air, à différentes pentes du pipeline et pour plusieurs valeurs du débit d'entrée, ont permis l'observation d'instabilités à grande échelle à faible débit de liquide et de gaz. Les cartes de configuration d'écoulement ont été établies pour trois pentes différentes du pipeline. Le modèle numérique développé à partir de ces données résout les équations locales instantanées de bilan de masse et de quantité de mouvement de ces écoulements par la méthode des caractéristiques. L'évolution des pressions, fraction de vide, débit de gaz et de liquide au cours du temps, prévue par le modèle, est généralement en bon accord avec les données expérimentales. Hydrodynamic instabilities of flow in pipeline/riser systems were studied on a test loop made of transparent tubes with an ID of 0. 053 m and 25 m long for the pipeline part and 13. 5 m long for the riser. Experiments performed with water and air, with different slopes of the pipeline and with several inlet flow rates, reveal large-scale instabilities at low liquid and gas flow rates. Flow configuration maps were compiled for three different pipeline slopes. The numerical model developed from these data solves instantaneous local equations for the mass balance and amount of movement of such flows by the method of characteristics. Variations in pressures, in the void fraction and in gas and liquid flow in the time forecast by the model are generally in good agreement with experimental data.

  3. Contribution to the theory of the two phase blowdown phenomenon

    International Nuclear Information System (INIS)

    In order to accurately model the two phase portion of a pressure vessel blowdown, it becomes necessary to understand the bubble growth mechanism within the vessel during the early period of the decompression, the two phase flow behavior within the vessel, and the applicability of the available two phase critical flow models to the blowdown transient. To aid in providing answers to such questions, a small scale, separate effects, isothermal blowdown experiment has been conducted in a small pressure vessel. The tests simulated a full open, double ended, guillotine break in a large diameter, short exhaust duct from the vessel. The vaporization process at the initiation of the decompression is apparently that of thermally dominated bubble growth originating from the surface cavities inside the system. Thermodynamic equilibrium of the remaining fluid within the vessel existed in the latter portion of the decompression. A nonuniform distribution of fluid quality within the vessel was also detected in this experiment. By comparison of the experimental results from this and other similar transient, two phase critical flow studies with steady state, small duct, two phase critical flow data, it is shown that transient, two phase critical flow in large ducts appears to be similar to steady state, two phase critical flow in small ducts. Analytical models have been developed to predict the blowdown characteristics of a system during subcooled decompression, the bubble growth regime of blowdown, and also in the nearly dispersed period of depressurization. This analysis indicates that the system pressure history early in the blowdown is dependent on the internal vessel surface area, the internal vessel volume, and also on the exhaust flow area from the system. This analysis also illustrates that the later period of decompression can be predicted based on thermodynamic equilibrium

  4. Crystalline fibrillar gel formation in aqueous surfactant-antioxidant system.

    Science.gov (United States)

    Joseph, Linet Rose; Tata, B V R; Sreejith, Lisa

    2015-08-01

    Cetyltrimethylammonium bromide (CTAB) is a well-known cationic surfactant capable to micellize into diverse morphologies in aqueous medium. We observed the formation of an opaque gel state from aqueous CTAB solution in the presence of the aromatic additive, para-coumaric acid (PCA). Optical microscopic images revealed the presence of large fibrils in the system at room temperature. Gel nature of the fibrils was confirmed by rheological measurements. Presence of interstitial water in the fibrils was recognized with Raman spectroscopy. On heating the sample above 30 (°) C, the fibrillar gel state changes to a transparent liquid state with Newtonian flow properties. Dynamic light scattering study hinted the presence of small micelles in the solution above 30 (°) C. Thus the system showed a temperature-dependent structural transition from opaque water-swollen gel to transparent micellar liquid. The formation of water-swollen fibrillar network is attributed to surfactant-additive intermolecular interactions in aqueous medium. Transition to micelle phase above 30 (°) C is related to Kraft transition which is observed at significantly lower temperature for CTAB in the absence of PCA. The structural features of PCA play a key role in promoting fibrillar network formation and elevating the Kraft transition in aqueous solution of CTAB.

  5. DESIGN OF ROBOTIC COLONIZER CONTROL SYSTEM FOR AQUEOUS ENVIRONMENT

    OpenAIRE

    C Venkatesh; C.CHANDRA SEKHAR

    2013-01-01

    Now a days there is a huge interest on underwater communication systems for various applications in order to explore aqueous environments. Intelligent robots and cooperative multi- agent robotic systems can be very efficient tools to speed up search and research operations in remote areas. Robots are also useful to do jobs inareas and in situations that are hazardous for human, they can go anywhere that is not reachable my humans and can go into gaps and move trough small holes that are impos...

  6. Performance tests of a two phase ejector

    Energy Technology Data Exchange (ETDEWEB)

    Harrell, G.S.; Kornhauser, A.A. [Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States). Dept. of Mechanical Engineering

    1995-12-31

    The ejector expansion refrigeration cycle is a modified vapor compression cycle in which a two phase ejector is used to recover a portion of the work otherwise lost in the expansion valve. The ejector improves cycle performance by increasing compressor inlet pressure and by lowering the quality of liquid entering the evaporator. Theoretically, a cooling COP improvement of approximately 23% is achievable for a typical refrigerating cycle and an ideal ejector. If the ejector performed as well as typical single phase ejectors an improvement of 12% could be achieved. Previous tests have demonstrated a smaller 3.7% improvement; the difference is in the poor performance of the two phase ejector. The purpose of this research is to understand the operating characteristics of the two phase ejector and to devise design improvements. A two phase ejector test rig has been constructed and tested. Preliminary data show performance superior to previously tested two phase ejectors, but still inferior to single phase ejectors. Ejector performance corresponds to refrigeration cycle COP improvements ranging from 3.9% to 7.6%.

  7. P450cam biocatalysis in surfactant-stabilized two-phase emulsions.

    Science.gov (United States)

    Ryan, Jessica D; Clark, Douglas S

    2008-04-15

    Cytochrome P450 monooxygenases (P450s) are powerful biocatalysts that have the ability to oxidize a broad range of substrates, often at non-reactive carbon centers. However, incorporation of P450s into synthetic schemes has so far been limited to a few whole-cell transformations. P450 substrates are often hydrophobic and have low water solubility, limiting the amount of product that can be produced. To help overcome this limitation, we have examined P450cam activity in two-phase hexane/water emulsions with and without the anionic surfactant, bis(2-ethylhexyl) sulfosuccinate sodium salt (AOT). Hydroxylation of camphor to hydroxycamphor by the three- component P450cam system was chosen as the model reaction, and regeneration of NADH was accomplished with yeast alcohol dehydrogenase (YADH). P450cam was activated in the surfactant-free emulsions, and addition of AOT improved the activity even further, at least over the range of camphor concentrations for which initial rates were readily measurable in all media. The largest observed rate enhancement was 4.5-fold. Nearly 50-times more product was formed in the surfactant-stabilized emulsions than was achieved in aqueous buffer, with total turnover numbers reaching 28,900 for P450cam and 11,800 for YADH. In the absence of surfactant, the two-phase reaction appeared to be mass-transfer limited, while inclusion of AOT alleviated transport limitations and/or afforded a larger interfacial area for P450 activation. The oxidation of hydroxycamphor to 2,5-diketocamphane was also observed, owing to the large concentration of hydroxycamphor relative to camphor in the aqueous phase of the two-phase emulsion. This competing reaction was accompanied by the uncoupled oxidation of NADH (i.e., NADH oxidation without formation of 2,5-diketocamphane), which reduced the availability of NADH for camphor oxidation and further limited the yield of hydroxycamphor in the two-phase emulsions. These results indicate that a surfactant

  8. Advanced Aqueous Separation Systems for Actinide Partitioning

    Energy Technology Data Exchange (ETDEWEB)

    Nash, Kenneth L.; Clark, Sue; Meier, G Patrick; Alexandratos, Spiro; Paine, Robert; Hancock, Robert; Ensor, Dale

    2012-03-21

    One of the most challenging aspects of advanced processing of spent nuclear fuel is the need to isolate transuranium elements from fission product lanthanides. This project expanded the scope of earlier investigations of americium (Am) partitioning from the lanthanides with the synthesis of new separations materials and a centralized focus on radiochemical characterization of the separation systems that could be developed based on these new materials. The primary objective of this program was to explore alternative materials for actinide separations and to link the design of new reagents for actinide separations to characterizations based on actinide chemistry. In the predominant trivalent oxidation state, the chemistry of lanthanides overlaps substantially with that of the trivalent actinides and their mutual separation is quite challenging.

  9. Pumped, Two-Phase Heat-Transfer Loop

    Science.gov (United States)

    Edelstein, F.

    1986-01-01

    Two-phase heat-transfer system delivers coolant to equipment as liquid and removes it as vapor. Alternatively, system heats equipment by delivering vapor and removing condensed liquid. Two-phase scheme effective for heat transfer over long distances. Heat-transfer plates remove heat from or supply heat to equipment. If temperature of plate is high, valve opens liquid-supply line to plate, and cooling results. If plate temperature is low, valve opens liquid-suction line to plate, and heating ensues.

  10. Definition of two-phase flow behaviors for spacecraft design

    Science.gov (United States)

    Reinarts, Thomas R.; Best, Frederick R.; Miller, Katherine M.; Hill, Wayne S.

    1991-01-01

    Data for complete models of two-phase flow in microgravity are taken from in-flight experiments and applied to an adiabatic flow-regime analysis to study the feasibility of two-phase systems for spacecraft. The data are taken from five in-flight experiments by Hill et al. (1990) in which a two-phase pump circulates a freon mixture and vapor and liquid flow streams are measured. Adiabatic flow regimes are analyzed based on the experimental superficial velocities of liquid and vapor, and comparisons are made with the results of two-phase flow regimes at 1 g. A motion analyzer records the flow characteristics at a rate of 1000 frames/sec, and stratified flow regimes are reported at 1 g. The flow regimes observed under microgravitational conditions are primarily annular and include slug and bubbly-slug regimes. The present data are of interest to the design and analysis of two-phase thermal-management systems for use in space missions.

  11. Study of two-phase flows in reduced gravity

    Science.gov (United States)

    Roy, Tirthankar

    Study of gas-liquid two-phase flows under reduced gravity conditions is extremely important. One of the major applications of gas-liquid two-phase flows under reduced gravity conditions is in the design of active thermal control systems for future space applications. Previous space crafts were characterized by low heat generation within the spacecraft which needed to be redistributed within the craft or rejected to space. This task could easily have been accomplished by pumped single-phase loops or passive systems such as heat pipes and so on. However with increase in heat generation within the space craft as predicted for future missions, pumped boiling two-phase flows are being considered. This is because of higher heat transfer co-efficients associated with boiling heat transfer among other advantages. Two-phase flows under reduced gravity conditions also find important applications in space propulsion as in space nuclear power reactors as well as in many other life support systems of space crafts. Two-fluid model along with Interfacial Area Transport Equation (IATE) is a useful tool available to predict the behavior of gas-liquid two-phase flows under reduced gravity conditions. It should be noted that considerable differences exist between two-phase flows under reduced and normal gravity conditions especially for low inertia flows. This is because due to suppression of the gravity field the gas-liquid two-phase flows take a considerable time to develop under reduced gravity conditions as compared to normal gravity conditions. Hence other common methods of analysis applicable for fully developed gas-liquid two-phase flows under normal gravity conditions, like flow regimes and flow regime transition criteria, will not be applicable to gas-liquid two-phase flows under reduced gravity conditions. However the two-fluid model and the IATE need to be evaluated first against detailed experimental data obtained under reduced gravity conditions. Although lot of studies

  12. Resolution of α-cyclohexyl-mandelic acid enantiomers by two-phase (O/W) recognition chiral extraction

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    This paper presents a new chiral separation technology: two-phase (O/W) recognition chiral extraction. Distribution behavior of α-cyclohexyl-mandelic acid enantiomers was studied in the extraction system with D(L)-isobutyl tartrate in 1,2-dichloroethane organic phase and β-CD derivatives in aqueous phase, and the influence of the kind and concentration of extractant and pH on extraction performance was investigated. The experimental results indicate that two-phase (O/W) recognition chiral extraction is of strong chiral separation ability. HP-β-CD, HE-β-CD and Me-β-CD have higher recognition ability for S-CHMA than that for R-CHMA, among which HP-β-CD has the strongest ability; whereas, D-isobutyl tartrate has reversed recognition ability for them. In the extraction system containing HP-β-CD and D-isobutyl tartrate, e.e.% of S-CHMA in aqueous phase reached 27.6% by one stage extraction, and the distribution ratio for R-CHMA(kR) and for S-CHMA(kS) and separation factor (α) are 2.44, 0.89 and 2.49, respectively. Meanwhile, pH and concentration of extractant have great effects on chiral separation ability. Two-phase (O/W) recognition chiral extraction has great significance for preparative separation of racemic compounds.

  13. INFLUENCE OF SURFACTANT ON TWO-PHASE FLOW REGIME AND PRESSURE DROP IN UPWARD INCLINED PIPES

    Institute of Scientific and Technical Information of China (English)

    XIA Guo-dong; CHAI Lei

    2012-01-01

    The influence of a surfactant on the two-phase flow regime and the pressure drop in upward inclined pipes is investigated for various gas/liquid flow rates.The air/water and air/100 ppm sodium dodecyl sulphate aqueous solution are used as the working fluids.The influence of the surfactant on the two-phase flow regime in upward inclined pipes is investigated using the electrical tomographic technique.For 0°,2.5° and 5° pipe inclinations,the surfactant has obvious effect on the transition from the stratified wavy flow to the annular flow,and the range of the stratified smooth flow regime is also extended to higher gas velocities.For 10°pipe inclination,no stratified flow regime is observed in the air/water flow.In the air/surfactant solution system,however,the stratified flow regime can be found in the range of USG =10m/s-28m/s and USL =0.07 m/s-0.2 m/s.For all inclination angles,the changes of the pressure gradient characteristics are accompanied with the flow pattern transitions.Adding surfactant in a two-phase flow would reduce the pressure gradient significantly in the slug flow and annular flow regimes.In the annular flow regime,the pressure gradient gradually becomes free of the influence of the upward inclined angle,and is only dependent on the property of the two-phase flow.

  14. Velocity and energy relaxation in two-phase flows

    CERN Document Server

    Meyapin, Yannick; Gisclon, Marguerite

    2009-01-01

    In the present study we investigate analytically the process of velocity and energy relaxation in two-phase flows. We begin our exposition by considering the so-called six equations two-phase model [Ishii1975, Rovarch2006]. This model assumes each phase to possess its own velocity and energy variables. Despite recent advances, the six equations model remains computationally expensive for many practical applications. Moreover, its advection operator may be non-hyperbolic which poses additional theoretical difficulties to construct robust numerical schemes |Ghidaglia et al, 2001]. In order to simplify this system, we complete momentum and energy conservation equations by relaxation terms. When relaxation characteristic time tends to zero, velocities and energies are constrained to tend to common values for both phases. As a result, we obtain a simple two-phase model which was recently proposed for simulation of violent aerated flows [Dias et al, 2010]. The preservation of invariant regions and incompressible li...

  15. Separation of Nanoparticles in Aqueous Multiphase Systems through Centrifugation

    KAUST Repository

    Akbulut, Ozge

    2012-08-08

    This paper demonstrates the use of aqueous multiphase systems (MuPSs) as media for rate-zonal centrifugation to separate nanoparticles of different shapes and sizes. The properties of MuPSs do not change with time or during centrifugation; this stability facilitates sample collection after separation. A three-phase system demonstrates the separation of the reaction products (nanorods, nanospheres, and large particles) of a synthesis of gold nanorods, and enriches the nanorods from 48 to 99% in less than ten minutes using a benchtop centrifuge. © 2012 American Chemical Society.

  16. An introduction to two-phase flows

    International Nuclear Information System (INIS)

    This course aims at proposing the necessary background for a rational approach to two-phase flows which are notably present in numerous industrial devices and equipment designed to perform energy transfer or mass transfer. The first part proposes a phenomenological approach to main two-phase flow structures and presents their governing variables. The second part presents some proven measurement techniques. The third part focuses on modelling. It recalls the equation elaboration techniques which are based on basic principles of mechanics and thermodynamics and on the application of different averaging operators to these principles. Some useful models are then presented such as models of pressure loss in a duct. The last chapter addresses some fundamental elements of heat transfers in ebullition and condensation

  17. Two-Phase Cavitating Flow in Turbomachines

    Directory of Open Access Journals (Sweden)

    Sandor I. Bernad

    2012-11-01

    Full Text Available Cavitating flows are notoriously complex because they are highly turbulent and unsteady flows involving two species (liquid/vapor with a large density difference. These features pose a unique challenge to numerical modeling works. The study briefly reviews the methodology curently employed for industrial cavitating flow simulations using the two-phase mixture model. The two-phase mixture model is evaluated and validated using benchmark problem where experimental data are available. A 3D cavitating flow computation is performed for the GAMM Francis runner. The model is able to qualitatively predict the location and extent of the 3D cavity on the blade, but further investigation are needed to quatitatively assess the accuracy for real turbomachinery cavitating flows.

  18. Two-phase flow of ferrofluids

    OpenAIRE

    Chi, Changqing

    2016-01-01

    Ferrofluids currently are the only type of magnetic liquid materials with wide practical use. The theory on ferrofluids is an example of success to apply statistics to science. Ferrofluids are two-phase liquids consisting of dispersed nanoscale ferromagnetic particles suspended in a carrier fluid. Due to their tiny size, individual ferromagnetic particles clearly exhibit Brownian motions. Only when a large number of randomly-moving particles are subject to an external magnetic field, can they...

  19. Two phase picture in driven polymer translocation

    OpenAIRE

    Saito, Takuya; Sakaue, Takahiro

    2012-01-01

    Two phase picture is a simple and effective methodology to capture the nonequilibrium dynamics of polymer associated with tension propagation. When applying it to the driven translocation process, there is a point to be noted, as briefly discussed in our recent article [Phys. Rev. E 85, 061803 (2012)]. In this article, we address this issue in detail and modify our previous prediction [Euro. Phys. J. E 34, 135 (2011)] by adopting an alternative steady-state ansatz. The modified scaling predic...

  20. 超声波辅助双水相提取条斑紫菜黄酮类物质及其抗氧化活性研究%Ultrasonic-Assisted Aqueous Two-Phase Extraction and Antioxidant Activity of Total Flavonoids from

    Institute of Scientific and Technical Information of China (English)

    陈利梅

    2012-01-01

    An ultrasonic-assisted aqueous two phase extraction method was presented for extracting total flavonoids from Porphyra yezoensisand the extraction conditions were optimized by an orthogonal array experimental design. Meanwhile, the hydroxyl free radical scavenging activity of total flavonoids from Porphyra yezoensis was determined. The results indicated that the method allowed effective extraction of total flavonoids. The extraction yield was 0.148%, which was significantly higher than that obtained by ethanol-water reflux extraction. The optimal extraction conditions were obtained as follows: n-propanol-to- water ratio 0.6, ammonium sulphate concentration 0.30 g/mL, ultrasonic treatment time 20 rain and material-to-liquid ratio 0.04. P. yezoensis abtmdanfly contained flavonoids and the total flavonoid extract from it had excellent hydroxyl free radical scavenging activity thus providing a good natural free radical scavenger.%利用超声波辅助丙醇-硫酸铵双水相体系提取紫菜中总黄酮,并优化提取条件,测定总黄酮提取物对羟自由基(·OH)的抑制活性。结果表明:本方法可有效地从紫菜中提取总黄酮,紫菜总黄酮提取率为0.148%,明显高于乙醇-水回流提取法。最优提取条件为醇水比为0.6、硫酸铵质量浓度0.30g/mL、超声时间20min、料液比0.04。紫菜中含有较丰富的黄酮类物质,提取物对·OH具有良好的抑制作用,是一种有效的天然自由基清除剂,具有很大的开发利用前景。

  1. On the modelling and the analysis of two-phase flow instabilities in pipeline-riser systems; Modelisation et analyse des instabilites d'ecoulements diphasiques dans les conduites petrolieres du type pipeline-riser

    Energy Technology Data Exchange (ETDEWEB)

    Zakarian, E.

    2000-03-10

    Recent estimations predict that over half the remaining offshore oil and gas reserves are located in deep water and marginal fields. For such reserves, economic recovery methods are required. Then, multiphase flows are transported within pipelines and separated on treatment platforms built in shallow water or processed in onshore facilities. Unfortunately, hydrodynamic instabilities may occur whenever gas and liquid flow in a pipeline, generating serious operating problems. This dissertation presents a new way to model two-phase flows in pipelines such as pipeline-riser systems. Equations are algebraic and differential. Their smoothness depends on the closure laws of the problem such as slip or friction laws. Smooth forms of these closure laws are presented for the first time in this dissertation. Therefore, a mathematical analysis of our model fits into a classical frame: a linear analysis leads to an analytical expression of the boundary between stable and unstable flows. A nonlinear analysis provides for the first time, the bifurcation curves of gas-liquid flows in pipe-riser systems, locally round their stability boundary. (author)

  2. Thermoreversible (Ionic-Liquid-Based) Aqueous Biphasic Systems.

    Science.gov (United States)

    Passos, Helena; Luís, Andreia; Coutinho, João A P; Freire, Mara G

    2016-02-04

    The ability to induce reversible phase transitions between homogeneous solutions and biphasic liquid-liquid systems, at pre-defined and suitable operating temperatures, is of crucial relevance in the design of separation processes. Ionic-liquid-based aqueous biphasic systems (IL-based ABS) have demonstrated superior performance as alternative extraction platforms, and their thermoreversible behaviour is here disclosed by the use of protic ILs. The applicability of the temperature-induced phase switching is further demonstrated with the complete extraction of two value-added proteins, achieved in a single-step. It is shown that these temperature-induced mono(bi)phasic systems are significantly more versatile than classical liquid-liquid systems which are constrained by their critical temperatures. IL-based ABS allow to work in a wide range of temperatures and compositions which can be tailored to fit the requirements of a given separation process.

  3. Thermoreversible (Ionic-Liquid-Based) Aqueous Biphasic Systems

    Science.gov (United States)

    Passos, Helena; Luís, Andreia; Coutinho, João A. P.; Freire, Mara G.

    2016-02-01

    The ability to induce reversible phase transitions between homogeneous solutions and biphasic liquid-liquid systems, at pre-defined and suitable operating temperatures, is of crucial relevance in the design of separation processes. Ionic-liquid-based aqueous biphasic systems (IL-based ABS) have demonstrated superior performance as alternative extraction platforms, and their thermoreversible behaviour is here disclosed by the use of protic ILs. The applicability of the temperature-induced phase switching is further demonstrated with the complete extraction of two value-added proteins, achieved in a single-step. It is shown that these temperature-induced mono(bi)phasic systems are significantly more versatile than classical liquid-liquid systems which are constrained by their critical temperatures. IL-based ABS allow to work in a wide range of temperatures and compositions which can be tailored to fit the requirements of a given separation process.

  4. Two-Phase Flow in Heterogeneous Media

    CERN Document Server

    Ghaffari, Hamed O

    2009-01-01

    In this study, we investigate the appeared complexity of two-phase flow (air-water) in a heterogeneous soil where the supposed porous media is non-deformable media which is under the time-dependent gas pressure. After obtaining of governing equations and considering the capillary pressure-saturation and permeability functions, the evolution of the models unknown parameters were obtained. In this way, using COMSOL (FEMLAB) and fluid flow-script Module, the role of heterogeneity in intrinsic permeability was analysed. Also, the evolution of relative permeability of wetting and non-wetting fluid, capillary pressure and other parameters were elicited.

  5. Analysis of Direct Samples of Early Solar System Aqueous Fluids

    Science.gov (United States)

    Zolensky, Michael E.; Bodnar, R J.; Fedele, L.; Yurimoto,H.; Itoh, S.; Fries, M.; Steele, A.

    2012-01-01

    Over the past three decades we have become increasingly aware of the fundamental importance of water, and aqueous alteration, on primitive solar-system bodies. Some carbonaceous and ordinary chondrites have been altered by interactions with liquid water within the first 10 million years after formation of their parent asteroids. Millimeter to centimeter-sized aggregates of purple halite containing aqueous fluid inclusions were found in the matrix of two freshly-fallen brecciated H chondrite falls, Monahans (1998, hereafter simply "Monahans") (H5) and Zag (H3-6) (Zolensky et al., 1999; Whitby et al., 2000; Bogard et al., 2001) In order to understand origin and evolution of the aqueous fluids inside these inclusions we much measure the actual fluid composition, and also learn the O and H isotopic composition of the water. It has taken a decade for laboratory analytical techniques to catch up to these particular nanomole-sized aqueous samples. We have recently been successful in (1) measuring the isotopic composition of H and O in the water in a few fluid inclusions from the Zag and Monahans halite, (2) mineralogical characterization of the solid mineral phases associated with the aqueous fluids within the halite, and (3) the first minor element analyses of the fluid itself. A Cameca ims-1270 equipped with a cryo-sample-stage of Hokkaido University was specially prepared for the O and H isotopic measurements. The cryo-sample-stage (Techno. I. S. Corp.) was cooled down to c.a. -190 C using liquid nitrogen at which the aqueous fluid in inclusions was frozen. We excavated the salt crystal surfaces to expose the frozen fluids using a 15 keV Cs+ beam and measured negative secondary ions. The secondary ions from deep craters of approximately 10 m in depth emitted stably but the intensities changed gradually during measurement cycles because of shifting states of charge compensation, resulting in rather poor reproducibility of multiple measurements of standard fluid

  6. DOE workshop: Sedimentary systems, aqueous and organic geochemistry

    Energy Technology Data Exchange (ETDEWEB)

    1993-07-01

    A DOE workshop on sedimentary systems, aqueous and organic geochemistry was held July 15-16, 1993 at Lawrence Berkeley Laboratory. Papers were organized into several sections: Fundamental Properties, containing papers on the thermodynamics of brines, minerals and aqueous electrolyte solutions; Geochemical Transport, covering 3-D imaging of drill core samples, hydrothermal geochemistry, chemical interactions in hydrocarbon reservoirs, fluid flow model application, among others; Rock-Water Interactions, with presentations on stable isotope systematics of fluid/rock interaction, fluid flow and petotectonic evolution, grain boundary transport, sulfur incorporation, tracers in geologic reservoirs, geothermal controls on oil-reservoir evolution, and mineral hydrolysis kinetics; Organic Geochemistry covered new methods for constraining time of hydrocarbon migration, kinetic models of petroleum formation, mudstones in burial diagenesis, compound-specific carbon isotope analysis of petroleums, stability of natural gas, sulfur in sedimentary organic matter, organic geochemistry of deep ocean sediments, direct speciation of metal by optical spectroscopies; and lastly, Sedimentary Systems, covering sequence stratigraphy, seismic reflectors and diagenetic changes in carbonates, geochemistry and origin of regional dolomites, and evidence of large comet or asteroid impacts at extinction boundaries.

  7. DOE workshop: Sedimentary systems, aqueous and organic geochemistry

    International Nuclear Information System (INIS)

    A DOE workshop on sedimentary systems, aqueous and organic geochemistry was held July 15-16, 1993 at Lawrence Berkeley Laboratory. Papers were organized into several sections: Fundamental Properties, containing papers on the thermodynamics of brines, minerals and aqueous electrolyte solutions; Geochemical Transport, covering 3-D imaging of drill core samples, hydrothermal geochemistry, chemical interactions in hydrocarbon reservoirs, fluid flow model application, among others; Rock-Water Interactions, with presentations on stable isotope systematics of fluid/rock interaction, fluid flow and petotectonic evolution, grain boundary transport, sulfur incorporation, tracers in geologic reservoirs, geothermal controls on oil-reservoir evolution, and mineral hydrolysis kinetics; Organic Geochemistry covered new methods for constraining time of hydrocarbon migration, kinetic models of petroleum formation, mudstones in burial diagenesis, compound-specific carbon isotope analysis of petroleums, stability of natural gas, sulfur in sedimentary organic matter, organic geochemistry of deep ocean sediments, direct speciation of metal by optical spectroscopies; and lastly, Sedimentary Systems, covering sequence stratigraphy, seismic reflectors and diagenetic changes in carbonates, geochemistry and origin of regional dolomites, and evidence of large comet or asteroid impacts at extinction boundaries

  8. Dynamic failure in two-phase materials

    Science.gov (United States)

    Fensin, S. J.; Walker, E. K.; Cerreta, E. K.; Trujillo, C. P.; Martinez, D. T.; Gray, G. T.

    2015-12-01

    Previous experimental research has shown that microstructural features such as interfaces, inclusions, vacancies, and heterogeneities can all act as void nucleation sites. However, it is not well understood how important these interfaces are to damage evolution and failure as a function of the surrounding parent materials. In this work, we present results on three different polycrystalline materials: (1) Cu, (2) Cu-24 wt. %Ag, and (3) Cu-15 wt. %Nb which were studied to probe the influence of bi-metal interfaces on void nucleation and growth. These materials were chosen due to the range of difference in structure and bulk properties between the two phases. The initial results suggest that when there are significant differences between the bulk properties (for example: stacking fault energy, melting temperature, etc.) the type of interface between the two parent materials does not principally control the damage nucleation and growth process. Rather, it is the "weaker" material that dictates the dynamic spall strength of the overall two-phase material.

  9. Enhancement of a novel extracellular uricase production by media optimization and partial purification by aqueous three-phase system.

    Science.gov (United States)

    Ram, Senthoor K; Raval, Keyur; JagadeeshBabu, P E

    2015-01-01

    Uricase (urate: oxygen oxidoreductase, EC 1.7.3.3), an enzyme belonging to the class of oxidoreductases, catalyzes the enzymatic oxidation of uric acid to allantoin and finds a wide variety of application as therapeutic and clinical reagent. In this study, uricase production ability of the bacterial strains isolated from deep litter poultry soil is investigated. The strain with maximum extracellular uricase production capability was identified as Xanthomonas fuscans subsp. aurantifolii based on 16S rRNA sequencing. Effect of various carbon and nitrogen sources on uricase productivity was investigated. The uricase production for this strain was optimized using statistically based experimental designs and resulted in uricase activity of 306 U/L, which is 2 times higher than initial uricase activity. Two-step purification, such as ammonium sulfate precipitation and aqueous two-phase system, was carried out and a twofold increase in yield and specific activity was observed.

  10. Design Of A Turgo Two-Phase Turbine Runner

    OpenAIRE

    Aaraj, Youssef; Mortada, Sorina; Clodic, Denis; Nemer, Maroun

    2014-01-01

    A two-phase impulse turbine used to replace the classic expansion valve in a refrigeration system needs a nozzle/expander to transform the flow stored enthalpy into kinetic energy, and a runner that comes afterwards to transform the flow kinetic energy into torque. That process transforms the isenthalpic expansion of the refrigerant into, ideally, an isentropic one. Replacing a classic isenthalpic expansion with a nearly isentropic one increases the cycle cooling capacity by 8% up to 20 % for...

  11. Phase appearance or disappearance in two-phase flows

    OpenAIRE

    Cordier, Floraine; Degond, Pierre; Kumbaro, Anela

    2011-01-01

    This paper is devoted to the treatment of specific numerical problems which appear when phase appearance or disappearance occurs in models of two-phase flows. Such models have crucial importance in many industrial areas such as nuclear power plant safety studies. In this paper, two outstanding problems are identified: first, the loss of hyperbolicity of the system when a phase appears or disappears and second, the lack of positivity of standard shock capturing schemes such as the Roe scheme. ...

  12. Eutectic Growth in Two-Phase Multicomponent Alloys

    OpenAIRE

    Senninger, Oriane; Voorhees, Peter W.

    2016-01-01

    A theory of two-phase eutectic growth for a multicomponent alloy is presented. This theory employs the thermodynamic equilibrium at the solid/liquid interface and thus makes it possible to use standard CALPHAD databases to determine the effects of multicomponent phase equilibrium on eutectic growth. Using the same hypotheses as the Jackson Hunt theory, we find that the growth law determined for binary alloys in the Jackson Hunt theory can be generalized to systems with N elements. In particul...

  13. MHD Generators Operating with Two-Phase Liquid Metal Flows

    International Nuclear Information System (INIS)

    A simplified one- component liquid metal MHD cycle which utilizes two-phase mixtures passing directly through the generator has been proposed and is being studied. Analysis indicates that a nuclear dual-cycle power system utilizing the proposed liquid metal conversion scheme as a topping cycle has overall efficiencies that are comparable to a plasma dual-cycle system at much lower,temperatures. The key to the potential of this cycle is the performance of the MHD generator operating with two-phase mixtures. A large NaK-N2 loop capable of accommodating both d.c. conduction or a.c. induction generators operating with either single-phase or two-phase flows has been built and recently put into operation. Recirculating NaK flow rates up to 200 gal/min and gas flows of 750 ft3/min can be obtained. The efficiency of a generator operating with two-phase flow will depend upon the nature of the flow and the degree to which the total entering liquid flow.interacts with the magnetic field. Because the flow pattern of a two-phase mixture changes from a dispersion of gas in liquid to a dispersion of liquid in gas as the mixture quality is increased, two different types of generators are proposed and are being studied. In the first generator, referred to as a film generator, the two-phase mixture enters at a slight angle to the lower surface of the generator. The liquid is separated by impingement. The high-velocity free surface liquid film that is formed interacts with a transverse magnetic film. The efficiency of this type of generator is a function of the separation ratio, skin friction and momentum losses. A 2 kW version of the generator has been built and is currently being run. Initial tests up to 250 W have been made, which have shown that the generator concept is feasible and that the flow is stable. This generator has run with inlet qualities to 0.05 and magnetic fields up to 12 kG. Measured voltages and amperages have ranged to 0.60 V and 60 A. It is planned to continue

  14. The Condensation effect on the two-phase flow stability

    International Nuclear Information System (INIS)

    A one-dimensional analytical model has been developed to be used for the linear analysis of density-wave oscillations in a parallel heated channel and a natural circulation loop.The heater and the riser sections are divided into a single-phase and a two-phase region.The two-phase region is represented by the drift-flux model. The model accounts for aphasic slip and subcooled boiling.The localized friction at the heater and the riser exit is treated considering the two-phase mixture.Also the effects of the condensation in the riser and the change in the system pressure have been studied.The exact equation for the heated channel and the total loop pressure drop is perturbed around the steady state.he stability characteristics of the heated channel and the loop are investigated using the Root finding method criterion.The results are summarized on instability maps in the plane of subcooled boiling number vs. phase change number (i.e., inlet subcooling vs. heater heat flux).The predictions of the model are compared with experimental results published in open literature. The results show that, the treatment effect of localized friction in two-phase mixtures stabilizes the system and improves the agreement of the calculations with the experimental results.For a parallel heated channel, the results indicate a more stable system with high inlet restriction, low outlet restriction, and high inlet velocity. And for a natural circulation loop, an increase in the inlet restriction broadened the range of the continuous circulation mode and stabilized the system, a decrease in the exit restriction or the liquid charging level shifted to the right the range of the continuous circulation mode and stabilized the system and an increase in the riser condensation shifted to the right the range of the continuous circulation mode and stabilized the system.The results show that the model agrees well with the available experimental data. In particular, the results show the significance of

  15. 一种新型两相励磁开关磁阻电机驱动系统的静态特性%STATIC PERFORMANCE OF A NEW SRD SYSTEM WITH TWO-PHASE EXCITATION

    Institute of Scientific and Technical Information of China (English)

    郭伟; 詹琼华; 丘亦慧

    2002-01-01

    该文主要分析了一种两相同时励磁的开关磁阻电机(SRM)的静态特性.文中首先简要介绍了这种两相励磁系统的结构,然后提出了两相励磁下SRM的磁链模型.基于详细的非线性有限元分析(FEA)的结果,建立了简化的线性模型且利用此线性模型导出了SRM的转矩--转角特性,并和非线性FEA模型下的结果进行了比较.最后,根据FEA的结果,提出了一种优化的控制策略来提高这种SRM的性能.%This paper provides an analysis of a switched reluctance motor (SRM) under two-phase excitation. After a brief introduction of the two-phase excitation scheme, the flux linkage model of a SRM under two-phase excitation is developed using FEA. A linearized model is then established based on the detailed flux linkage analysis. The torque-angle characteristics of such a linear model are compared with that derived from the detailed and nonlinear FEA model. Based on theFEA model, an optimized control strategy is proposed to improve the performanceof the SRM under two-phase excitation.

  16. Energy efficient two-phase cooling for concentrated photovoltaic arrays

    Science.gov (United States)

    Reeser, Alexander Douglas

    Concentrated sunlight focused on the aperture of a photovoltaic solar cell, coupled with high efficiency, triple junction cells can produce much greater power densities than traditional 1 sun photovoltaic cells. However, the large concentration ratios will lead to very high cell temperatures if not efficiently cooled by a thermal management system. Two phase, flow boiling is an attractive cooling option for such CPV arrays. In this work, two phase flow boiling in mini/microchannels and micro pin fin arrays will be explored as a possible CPV cooling technique. The most energy efficient microchannel design is chosen based on a least-material, least-energy analysis. Heat transfer and pressure drop obtained in micro pin fins will be compared to data in the recent literature and new correlations for heat transfer coefficient and pressure drop will be presented. The work concludes with an energy efficiency comparison of micro pin fins with geometrically similar microchannel geometry.

  17. Gelfand-type problem for two-phase porous media.

    Science.gov (United States)

    Gordon, Peter V; Moroz, Vitaly

    2014-03-01

    We consider a generalization of the Gelfand problem arising in Frank-Kamenetskii theory of thermal explosion. This generalization is a natural extension of the Gelfand problem to two-phase materials, where, in contrast to the classical Gelfand problem which uses a single temperature approach, the state of the system is described by two different temperatures. We show that similar to the classical Gelfand problem the thermal explosion occurs exclusively owing to the absence of stationary temperature distribution. We also show that the presence of interphase heat exchange delays a thermal explosion. Moreover, we prove that in the limit of infinite heat exchange between phases the problem of thermal explosion in two-phase porous media reduces to the classical Gelfand problem with renormalized constants.

  18. Cold water injection into two-phase mixtures

    International Nuclear Information System (INIS)

    This report presents the results of a review of the international literature regarding the dynamic loadings associated with the injection of cold water into two-phase mixtures. The review placed emphasis on waterhammer in nuclear power plants. Waterhammmer incidence data were reviewed for information related to thermalhydraulic conditions, underlying causes and consequential damage. Condensation induced waterhammer was found to be the most significant consequence of injecting cold water into a two-phase system. Several severe waterhammer incidents have been attributed to slug formation and steam bubble collapse under conditions of stratified steam and cold water flows. These phenomena are complex and not well understood. The current body of experimental and analytical knowledge is not large enough to establish maps of expected regimes of condensation induced waterhammer. The Electric Power Research Institute, in the United States, has undertaken a major research and development programme to develop the knowledge base for this area. The limited models and data currently available show that mechanical parameters are as important as thermodynamic conditions for the initiation of condensation induced waterhammer. Examples of bounds for avoiding two-phase waterhammer are given. These bounds are system specific and depend upon parameters such as pump capacity, pipe length and pipe orientation

  19. 四相SRM驱动系统两相励磁功率因数校正研究%Power factor correction for 4 phases switched reluctance motors drive system under two-phase excitation

    Institute of Scientific and Technical Information of China (English)

    高洁; 孙鹤旭; 何林; 董砚; 郑易

    2011-01-01

    针对开关磁阻电机传统功率拓扑结构电源侧电流畸变严重,功率因数较低的问题,通过将电容后置,并且增加相应的开关管和二极管,提出一种功率拓扑结构,将其应用于两相励磁条件下的四相SRM进行功率因数校正.对该功率拓扑结构及其电容补偿方案进行了机理分析,基于Matlab/SIMULINK构建了四相开关磁阻电机驱动系统两相导通模式功率因数校正拓扑结构模型,对开关磁阻电机电压、电流、转矩等进行了全面仿真研究,验证了所提出方案的可行性及有效性.仿真结果表明,该拓扑结构不但可以改善系统的功率因数,并且减小了因电源波动引起的转矩脉动,优化了电机的起动性能,提高了效率.%In traditional power topological structure of Switched Reluctance Motor (SRM) , for the serious current distortion in power supply side and its result in the low power factor, by the use of the rear capacitance and increase the corresponding switch tube and diode, a new topological structure was presented, and was applied in traditional structure for power factor correction (PFC). The mechanism of new power topological structure and the capacitor compensation schemes were analyzed, four phases Switched Reluctance Motor Drive (SRD) system power factor correction topology structure with two phase conduction mode was modeling based on MATLAB/SIMULINK, and a comprehensive simulation study of SRM voltage, current, torque, etc. Was analyzed. It verifies the effectiveness and the feasibility the proposed scheme. The simulation results show that the topology structure can not only improve the power factor of system and reduce the torque ripple caused by power fluctuating, the motor starting performance is optimized and the system efficiency is improved.

  20. DESIGN OF ROBOTIC COLONIZER CONTROL SYSTEM FOR AQUEOUS ENVIRONMENT

    Directory of Open Access Journals (Sweden)

    C.VENKATESH

    2013-05-01

    Full Text Available Now a days there is a huge interest on underwater communication systems for various applications in order to explore aqueous environments. Intelligent robots and cooperative multi- agent robotic systems can be very efficient tools to speed up search and research operations in remote areas. Robots are also useful to do jobs inareas and in situations that are hazardous for human, they can go anywhere that is not reachable my humans and can go into gaps and move trough small holes that are impossible for humans and even trained dogs. in this paper, a wireless underwater mobile robot system is designed in order to study the behavior of artemia group. anew idea has been presented for underwater mobile robot system which is consists of two parts, first is the underwater mechanical robot and the second is ZigBee wireless based mobile robot which controls and moves the first part. by this system different patterns motion control (linear, circular, zigzag, etc. has been performed and proved the ability to control group of robot by controlling the group of artemia and monitoring the underwater mobile robot control with the help of water proof RF wireless camera and also explore the details present around the mobile robot

  1. Microreactor concepts for enhanced mass transfer in the two-phase hydroformylation of 1-octene

    Energy Technology Data Exchange (ETDEWEB)

    Dietzsch, E.; Mueller, J.; Voelkel, N.; Klemm, E. [Chemnitz Univ. of Technology (Germany). Dept. of Chemical Technology

    2006-07-01

    Using higher olefins such as 1-octene in the so called two-phase hydroformylation technology with a water soluble catalyst, the observed reaction rates are much slower than that of short chain alkenes, because the mass transfer of 1-octene to the aqueous catalyst phase can be assumed as a rate limiting step. A solution for this problem preserving the advantages of the two-phase technology is the application of microreactors. Using them, a process intensification should be achieved because of their superior intrinsic interface areas between different phases. In preliminary studies we investigated different mixing concepts for generating optimum and stable G/L/L-mixtures of synthesis gas, 1-octene and catalyst solution which were subsequently fed to a capillary microreactor conducting the hydroformylation. Since the mass transport of 1-octene into the aqueous catalyst phase should be the mainly limiting step, it was the aim to achieve a maximum dispersion of the organic in the aqueous phase. For comparison purposes investigations of the two-phase hydroformylation of 1-octene in a continuous stirred autoclave were performed. These experiments are the basis to evaluate and quantify a process intensification by the use of microreactors in the hydroformylation according to the two-phase technology. (orig.)

  2. Condensation in a two-phase pool

    International Nuclear Information System (INIS)

    We consider the case of vapor condensation in a liquid pool, when the heat transfer is controlled by heat losses through the walls. The analysis is based on drift flux theory for phase separation in the pool, and determines the two-phase mixture height for the pool. To our knowledge this is the first analytical treatment of this classic problem that gives an explicit result, previous work having established the result for the evaporative case. From conservation of mass and energy in a one-dimensional steady flow, together with a void relation between the liquid and vapor fluxes, we determine the increase in the mixture level from the base level of the pool. It can be seen that the thermal and hydrodynamic influences are separable. Thus, the thermal influence of the wall heat transfer appears through its effect on the condensing length L*, so that at high condensation rates the pool is all liquid, and at low rates overflows (the level swell or foaming effect). Similarly, the phase separation effect hydrodynamically determines the height via the relative velocity of the mixture to the entering flux. We examine some practical applications of this result to level swell in condensing flows, and also examine some limits in ideal cases

  3. Research of High Precision Control System of Two-phase Hybrid Stepping Motor%高精度二相混合式步进电机控制系统研究

    Institute of Scientific and Technical Information of China (English)

    付朝阳; 刘景林; 常威威

    2009-01-01

    On the basis of the mathematics model of two-phase hybrid stepper motor, aiming at solving the problem of loud noise and large vibration in the low-speed operation, the paper studies the technology of sine pulse width modulation subdivided driving and a multi-micro stepping driver based on the one-chip computer controlling was designed. The driver consists of digital control part, GAL logic integrated unit, SG3525 constant current control circuit, driving circuit, over current protecting and feedback circuit, and the power supply block. The driving system using special integrated chip and programmable logic device takes 8-bit single chip AT89C2051 as the control core and has the functions of constant current control, forward/reverse working, over-current protection and multilevel subdivided driving. Experiments indicate that the design of hardware and software is reasonable and feasible, and successfully meets the design needs.%在二相混合式步进电机数学模型的基础上,针对电机低速运行时的振动和噪声过大的问题,研究了正弦脉宽调制细分驱动技术,开发出一种新型的基于单片机的多细分二相混合式步进电机驱动器.该系统主要分为数字控制部分、GAL片逻辑综合信号处理单元、SG3525恒流控制电路、驱动功放电路、过流保护及反馈电路和系统供电电源模块等.系统采用专用集成芯片和可编程逻辑器件,以8位单片机AT89C2051为控制核心.实现恒流控制、正/反转运行、过流保护和多档位细分等功能.实验结果表明,系统硬件和软件设计合理可行,各项技术指标均达到了设计要求.

  4. Design and construction of two phases flow meter

    International Nuclear Information System (INIS)

    This paper deals with design of the gamma ray correlometer and flow loop system for measuring the velocity between two parallel cross-sections of a pipeline. In the laboratory, the radioisotope source and detector were collimated by brass with small beam slit respectively. The flow loop system consists of transparent pipeline, adjustable frequency pump and water container. As a result, when the construction of the flow loop and correlometer is completed, the velocity of two phases flow can be measured by the cross-correlation techniques. (Author)

  5. Monodisperse PEGylated spheres: an aqueous colloidal model system.

    Science.gov (United States)

    Ulama, Jeanette; Zackrisson Oskolkova, Malin; Bergenholtz, Johan

    2014-03-01

    Fluorinated core-shell spheres have been synthesized using a novel semibatch emulsion polymerization protocol employing slow feeding of the initiator. The synthesis results in aqueous dispersions of highly monodisperse spheres bearing a well-defined poly(ethylene glycol) graft (PEGylation). Measurements are consistent with the synthesis achieving a high grafting density that moreover consists of a single PEG layer with the polymer significantly elongated beyond its radius of gyration in bulk. The fluorination of the core of the particles confers a low index of refraction such that the particles can be refractive index matched in water through addition of relatively small amounts of a cosolvent, which enables the use of optical and laser-based methods for studies of concentrated systems. The systems exhibit an extreme stability in NaCl solutions, but attractions among particles can be introduced by addition of other salts, in which case aggregation is shown to be reversible. The PEGylated sphere dispersions are expected to be ideally suited as model systems for studies of the effect of PEG-mediated interactions on, for instance, structure, dynamics, phase behavior, and rheology. PMID:24533774

  6. Ostwald ripening in two-phase mixtures

    International Nuclear Information System (INIS)

    Experimental measurements of the temperature of a rapidly solidified solid-liquid mixture have been made over a range of volume fractions solid 0.23 to 0.95. These experiments demonstrate the viability of measuring the change in interfacial curvature with time via precision thermometry. The experimental measurements also indicate that there is no radical change in interface morphology over a wide range of volume fractions solid. A solution to the multi-particle diffusion problem (MDP) has been constructed through the use of potential theory. The solution to the MDP was used to describe the diffusion field within a coarsening two-phase mixture consisting of dispersed spherical second-phase particles. Since this theory is based upon the MDP, interparticle diffusional interactions are specifically included in the treatment. As a result, the theory yields, for the first time, insights into the influence of the local distribution of curvature on a particle's coarsening rate. The effect of interparticle interactions on the collective behavior of an ensemble of coarsening particles was also investigated. It was found that any arbitrary distribution of particle radii will tend to a specific time independent distribution when the particle radii are scaled by the average particle radius. Furthermore, it was determined that with increasing volume fraction of coarsening phase, these time independent distributions become broader and more symmetric. It was also found that the ripening kinetics, as measured by the growth rate of the average particle size, increases by a factor of five upon increasing the volume fraction of coarsening phase from zero to 0.5

  7. ENVIRONMENTAL TECHNOLOGY VERIFICATION REPORT; ULTRASONIC AQUEOUS CLEANING SYSTEMS, SMART SONIC CORPORATION, SMART SONIC

    Science.gov (United States)

    This report is a product of the U.S. EPA's Environmental Technoloy Verification (ETV) Program and is focused on the Smart Sonics Ultrasonic Aqueous Cleaning Systems. The verification is based on three main objectives. (1) The Smart Sonic Aqueous Cleaning Systems, Model 2000 and...

  8. Reticulation of Aqueous Polyurethane Systems Controlled by DSC Method

    Directory of Open Access Journals (Sweden)

    Jakov Stamenkovic

    2006-06-01

    Full Text Available The DSC method has been employed to monitor the kinetics of reticulation ofaqueous polyurethane systems without catalysts, and with the commercial catalyst of zirconium(CAT®XC-6212 and the highly selective manganese catalyst, the complex Mn(III-diacetylacetonemaleinate (MAM. Among the polyol components, the acrylic emulsions wereused for reticulation in this research, and as suitable reticulation agents the water emulsiblealiphatic polyisocyanates based on hexamethylendoisocyanate with the different contents ofNCO-groups were employed. On the basis of DSC analysis, applying the methods of Kissinger,Freeman-Carroll and Crane-Ellerstein the pseudo kinetic parameters of the reticulation reactionof aqueous systems were determined. The temperature of the examination ranged from 50oC to450oC with the heat rate of 0.5oC/min. The reduction of the activation energy and the increaseof the standard deviation indicate the catalytic action of the selective catalysts of zirconium andmanganese. The impact of the catalysts on the reduction of the activation energy is thestrongest when using the catalysts of manganese and applying all the three afore-said methods.The least aberrations among the stated methods in defining the kinetic parameters wereobtained by using the manganese catalyst.

  9. Investigation of Power Losses of Two-Stage Two-Phase Converter with Two-Phase Motor

    Directory of Open Access Journals (Sweden)

    Michal Prazenica

    2011-01-01

    Full Text Available The paper deals with determination of losses of two-stage power electronic system with two-phase variable orthogonal output. The simulation is focused on the investigation of losses in the converter during one period in steady-state operation. Modeling and simulation of two matrix converters with R-L load is shown in the paper. The simulation results confirm a very good time-waveform of the phase current and the system seems to be suitable for low-cost application in automotive/aerospace industries and in application with high frequency voltage sources.

  10. Vapor Compressor Driven Hybrid Two-Phase Loop Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This Small Business Innovation Research Phase I project will demonstrate a vapor compressor driven hybrid two-phase loop technology. The hybrid two-phase loop...

  11. 气液混输悬链线立管系统两相流特性实验%EXPERIMENTS ON TWO-PHASE FLOW CHARACTERISTICS IN A CATENARY RISER SYSTEM WITH THE GAS AND LIQUID MIXTURE TRANSPORTATION

    Institute of Scientific and Technical Information of China (English)

    高嵩; 李巍; 尤云祥; 俞忠; 胡天群

    2012-01-01

    Severe slugging is an undesirable flow phenomenon for a pipline-riser system with the gas-liquid mixture transportation in ocean engineering. In present paper experiments were performed for the two-phase flow characteristics in a horizontal/declination pipeline-catenary riser system with the gas-liquid mixture transportation, and flow patterns were identified by series combinations of gas and liquid superficial velocities, including severe slug, intermittent and oscillation flows. The formation mechanisms of these flow patterns were presented and the conditions where the severe slug flow can be produced in the catenary riser were obtained. The results show that the severe slug flow in a catenary riser has remarkably periodic characteristics and consists of four stages in a circle, including slug formation, slug production, slug blowout and liquid fallback, respectively, where the characteristics of the flow parameters in each stage were given. Moreover, the formation mechanisms of severe slug flows in both catenary and vertical risers were compared and analyzed, and a remarkable differenti- ation in the slug formation stages for the two types of risers was observed, where the formation procedure of a mixture liquid slug with both gas and liquid first occurs before the pure liquid slug in the catenary riser can be produced, however, there is no occurrence of such a procedure of the mixture liquid slug for the vertical riser.%严重段塞流是海洋工程气液混输管线-立管系统中常见的一种特殊有害流动现象,采用水平-下倾-悬链线立管气液混输组合管道系统,通过系列实验在悬链线立管中获得了严重段塞流、间歇流和震荡流等流型,阐述了这些流动现象的形成机理,提出了能够产生严重段塞流的判定准则.结果表明,悬链线立管严重段塞流具有明显周期性,在一个周期内的流动特征可分为液塞形成、液体出流、液气喷发及液体回流等4个阶段,进而给

  12. Modeling transient two-phase stratified flow in pipelines

    International Nuclear Information System (INIS)

    An isothermal, two-fluid model, comprised of separate mass and linear momentum conservation equations for the gas and liquid phases was formulated. Interfacial mass transfer effects were modeled via the black oil method. Both equal and unequal phase pressure formulations were evaluated. The model was used to investigate transient two-phase stratified flow in pipelines. An explicit numerical scheme was used to solve the system of equations. Experimental data were collected in an existing 425 m long, 76.2 mm diameter horizontal pipeline. Good agreement was observed between experimental and predicted results

  13. Spectral Optical Coherence Tomography Using Two-Phase Shifting Method

    Institute of Scientific and Technical Information of China (English)

    MA Zhen-He; Ruikang K. Wang; ZHANG Fan; YAO Jian-Quan

    2005-01-01

    @@ A two-phase shifting method is introduced to eliminate the strong autocorrelation noise inherent in spectral optical coherence tomography and to mitigate the unwanted auto- and cross-coherent terms introduced by the reflections from various optical interfaces present in the system. Furthermore, this method is also able to amplify the desired signal by a factor of 2. The feasibility of such a method is demonstrated using a mirror-like object. An intact porcine cornea tissue in vitro is also used to show the potential of this method for biological imaging.

  14. Distribution behavior of superparamagnetic carbon nanotubes in an aqueous system.

    Science.gov (United States)

    Bai, Xue; Liu, Yuqi; Yu, Lu; Hua, Zulin

    2016-01-01

    This study investigates the distribution behavior of superparamagnetic multiwalled carbon nanotubes (SPM-MWCNTs) in an aqueous system containing Lake Tai sediment. Specifically, the effects of dissolved organic matter (DOM) and sediment on SPM-MWCNTs under various conditions and the interaction forms between them were evaluated through a modified mathematical model and characterization. The results showed that DOM can stabilize SPM-MWCNTs by providing sterically and electrostatically stable surfaces, even under high sodium concentrations. The fitting accuracy of the Freundlich adsorption isotherm is higher than that of the Langmuir adsorption isotherm. Therefore, the adsorption of SPM-MWCNT on the sediment should proceed through a multiple, complex and heterogeneous adsorption mechanism. Characterization analyses indicated that DOM may serve as a bridge for the inorganic adsorption between SPM-MWCNTs and sediment. This study is the first to investigate the distribution behavior of magnetite coated carbon nanotubes (CNTs), which simplified the separation and quantification considerably. The findings of this study will serve as a valuable reference for future studies of magnetic CNTs. PMID:27599569

  15. Experimental and numerical investigation on two-phase flow instabilities

    Energy Technology Data Exchange (ETDEWEB)

    Ruspini, Leonardo Carlos

    2013-03-01

    Two-phase flow instabilities are experimentally and numerically studied within this thesis. In particular, the phenomena called Ledinegg instability, density wave oscillations and pressure drop oscillations are investigated. The most important investigations regarding the occurrence of two-phase flow instabilities are reviewed. An extensive description of the main contributions in the experimental and analytical research is presented. In addition, a critical discussion and recommendations for future investigations are presented. A numerical framework using a hp-adaptive method is developed in order to solve the conservation equations modelling general thermo-hydraulic systems. A natural convection problem is analysed numerically in order to test the numerical solver. Moreover, the description of an adaptive strategy to solve thermo-hydraulic problems is presented. In the second part of this dissertation, a homogeneous model is used to study Ledinegg, density wave and pressure drop oscillations phenomena numerically. The dynamic characteristics of the Ledinegg (flow excursion) phenomenon are analysed through the simulation of several transient examples. In addition, density wave instabilities in boiling and condensing systems are investigated. The effects of several parameters, such as the fluid inertia and compressibility volumes, on the stability limits of Ledinegg and density wave instabilities are studied, showing a strong influence of these parameters. Moreover, the phenomenon called pressure drop oscillations is numerically investigated. A discussion of the physical representation of several models is presented with reference to the obtained numerical results. Finally, the influence of different parameters on these phenomena is analysed. In the last part, an experimental investigation of these phenomena is presented. The designing methodology used for the construction of the experimental facility is described. Several simulations and a non

  16. Reynolds transport theorem for a two-phase flow

    Science.gov (United States)

    Collado, Francisco J.

    2007-01-01

    Transport equations for one-dimensional (1d), steady, two-phase flow have been proposed based on the fact that if the phases have different velocities, they cannot cover the same distance (the control volume length) in the same time. Thus, working in the same control volume for the two phases, the time scales of the phases have to be different. From this approach, transport balances for 1D, steady, two-phase flow have been already derived, supplying acceptable correlations for two-phase flow. Here, based on the strict application of the Reynolds transport theorem, general transport balances for two-phase flow are suggested.

  17. Experimental study of two-phase natural circulation circuit

    Energy Technology Data Exchange (ETDEWEB)

    Lemos, Wanderley Freitas; Su, Jian, E-mail: wlemos@lasme.coppe.ufrj.br, E-mail: sujian@nuclear.ufrj.br [Coordenacao dos Programas de Pos-Graduacao em Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Nuclear; Faccini, Jose Luiz Horacio, E-mail: faccini@ien.gov.br [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), RIo de Janeiro, RJ (Brazil). Lab. de Termo-Hidraulica Experimental

    2012-07-01

    This paper reports an experimental study on the behavior of fluid flow in natural circulation under single-and two-phase flow conditions. The natural circulation circuit was designed based on concepts of similarity and scale in proportion to the actual operating conditions of a nuclear reactor. This test equipment has similar performance to the passive system for removal of residual heat presents in Advanced Pressurized Water Reactors (A PWR). The experiment was carried out by supplying water to primary and secondary circuits, as well as electrical power resistors installed inside the heater. Power controller has available to adjust the values for supply of electrical power resistors, in order to simulate conditions of decay of power from the nuclear reactor in steady state. Data acquisition system allows the measurement and control of the temperature at different points by means of thermocouples installed at several points along the circuit. The behavior of the phenomenon of natural circulation was monitored by a software with graphical interface, showing the evolution of temperature measurement points and the results stored in digital format spreadsheets. Besides, the natural circulation flow rate was measured by a flowmeter installed on the hot leg. A flow visualization technique was used the for identifying vertical flow regimes of two-phase natural circulation. Finally, the Reynolds Number was calculated for the establishment of a friction factor correlation dependent on the scale geometrical length, height and diameter of the pipe. (author)

  18. A real two-phase submarine debris flow and tsunami

    International Nuclear Information System (INIS)

    The general two-phase debris flow model proposed by Pudasaini is employed to study subaerial and submarine debris flows, and the tsunami generated by the debris impact at lakes and oceans. The model, which includes three fundamentally new and dominant physical aspects such as enhanced viscous stress, virtual mass, and generalized drag (in addition to buoyancy), constitutes the most generalized two-phase flow model to date. The advantage of this two-phase debris flow model over classical single-phase, or quasi-two-phase models, is that the initial mass can be divided into several parts by appropriately considering the solid volume fraction. These parts include a dry (landslide or rock slide), a fluid (water or muddy water; e.g., dams, rivers), and a general debris mixture material as needed in real flow simulations. This innovative formulation provides an opportunity, within a single framework, to simultaneously simulate the sliding debris (or landslide), the water lake or ocean, the debris impact at the lake or ocean, the tsunami generation and propagation, the mixing and separation between the solid and fluid phases, and the sediment transport and deposition process in the bathymetric surface. Applications of this model include (a) sediment transport on hill slopes, river streams, hydraulic channels (e.g., hydropower dams and plants); lakes, fjords, coastal lines, and aquatic ecology; and (b) submarine debris impact and the rupture of fiber optic, submarine cables and pipelines along the ocean floor, and damage to offshore drilling platforms. Numerical simulations reveal that the dynamics of debris impact induced tsunamis in mountain lakes or oceans are fundamentally different than the tsunami generated by pure rock avalanches and landslides. The analysis includes the generation, amplification and propagation of super tsunami waves and run-ups along coastlines, debris slide and deposition at the bottom floor, and debris shock waves. It is observed that the

  19. A real two-phase submarine debris flow and tsunami

    Science.gov (United States)

    Pudasaini, Shiva P.; Miller, Stephen A.

    2012-09-01

    The general two-phase debris flow model proposed by Pudasaini [1] is employed to study subaerial and submarine debris flows, and the tsunami generated by the debris impact at lakes and oceans. The model, which includes three fundamentally new and dominant physical aspects such as enhanced viscous stress, virtual mass, and generalized drag (in addition to buoyancy), constitutes the most generalized two-phase flow model to date. The advantage of this two-phase debris flow model over classical single-phase, or quasi-two-phase models, is that the initial mass can be divided into several parts by appropriately considering the solid volume fraction. These parts include a dry (landslide or rock slide), a fluid (water or muddy water; e.g., dams, rivers), and a general debris mixture material as needed in real flow simulations. This innovative formulation provides an opportunity, within a single framework, to simultaneously simulate the sliding debris (or landslide), the water lake or ocean, the debris impact at the lake or ocean, the tsunami generation and propagation, the mixing and separation between the solid and fluid phases, and the sediment transport and deposition process in the bathymetric surface. Applications of this model include (a) sediment transport on hill slopes, river streams, hydraulic channels (e.g., hydropower dams and plants); lakes, fjords, coastal lines, and aquatic ecology; and (b) submarine debris impact and the rupture of fiber optic, submarine cables and pipelines along the ocean floor, and damage to offshore drilling platforms. Numerical simulations reveal that the dynamics of debris impact induced tsunamis in mountain lakes or oceans are fundamentally different than the tsunami generated by pure rock avalanches and landslides. The analysis includes the generation, amplification and propagation of super tsunami waves and run-ups along coastlines, debris slide and deposition at the bottom floor, and debris shock waves. It is observed that the

  20. A real two-phase submarine debris flow and tsunami

    Energy Technology Data Exchange (ETDEWEB)

    Pudasaini, Shiva P.; Miller, Stephen A. [Department of Geodynamics and Geophysics, Steinmann Institute, University of Bonn Nussallee 8, D-53115, Bonn (Germany)

    2012-09-26

    The general two-phase debris flow model proposed by Pudasaini is employed to study subaerial and submarine debris flows, and the tsunami generated by the debris impact at lakes and oceans. The model, which includes three fundamentally new and dominant physical aspects such as enhanced viscous stress, virtual mass, and generalized drag (in addition to buoyancy), constitutes the most generalized two-phase flow model to date. The advantage of this two-phase debris flow model over classical single-phase, or quasi-two-phase models, is that the initial mass can be divided into several parts by appropriately considering the solid volume fraction. These parts include a dry (landslide or rock slide), a fluid (water or muddy water; e.g., dams, rivers), and a general debris mixture material as needed in real flow simulations. This innovative formulation provides an opportunity, within a single framework, to simultaneously simulate the sliding debris (or landslide), the water lake or ocean, the debris impact at the lake or ocean, the tsunami generation and propagation, the mixing and separation between the solid and fluid phases, and the sediment transport and deposition process in the bathymetric surface. Applications of this model include (a) sediment transport on hill slopes, river streams, hydraulic channels (e.g., hydropower dams and plants); lakes, fjords, coastal lines, and aquatic ecology; and (b) submarine debris impact and the rupture of fiber optic, submarine cables and pipelines along the ocean floor, and damage to offshore drilling platforms. Numerical simulations reveal that the dynamics of debris impact induced tsunamis in mountain lakes or oceans are fundamentally different than the tsunami generated by pure rock avalanches and landslides. The analysis includes the generation, amplification and propagation of super tsunami waves and run-ups along coastlines, debris slide and deposition at the bottom floor, and debris shock waves. It is observed that the

  1. Unsteady interfacial coupling of two-phase flow models

    International Nuclear Information System (INIS)

    The primary coolant circuit in a nuclear power plant contains several distinct components (vessel, core, pipes,...). For all components, specific codes based on the discretization of partial differential equations have already been developed. In order to obtain simulations for the whole circuit, the interfacial coupling of these codes is required. The approach examined within this work consists in coupling codes by providing unsteady information through the coupling interface. The numerical technique relies on the use of an interface model, which is combined with the basic strategy that was introduced by Greenberg and Leroux in order to compute approximations of steady solutions of non-homogeneous hyperbolic systems. Three different coupling cases have been examined: (i) the coupling of a one-dimensional Euler system with a two-dimensional Euler system; (ii) the coupling of two distinct homogeneous two-phase flow models; (iii) the coupling of a four-equation homogeneous model with the standard two-fluid model. (author)

  2. Study on Two-Phase Flow in Heterogeneous Porous Media by Light Transmission Method

    Science.gov (United States)

    Qiao, W.

    2015-12-01

    The non-aqueous phase liquid (NAPL) released to the subsurface can form residual ganglia and globules occupying pores and also accumulate and form pools, in which multiphase system forms. Determining transient fluid saturations in a multiphase system is essential to understand the flow characteristics of systems and to perform effective remediation strategies. As a non-destructive and non-invasive laboratory technique utilized for the measurement of liquid saturation in porous media, light transmission is of the lowest cost and safe. Utilization of Coupled Charge Device camera in light transmission systems provides a nearly instantaneous high-density array of spatial measurements over a very large dynamic range. The migration of NAPL and air spariging technique applied to remove NAPL in aquifer systems are typically two-phase flow problem. Because of the natural aquifer normally being heterogeneous, two 2-D sandboxes (Length55cm×width1.3cm×hight45cm) are set up to study the migration of gas and DNAPL in heterogeneous porous media based on light transmission method and its application in two-phase flow. Model D for water/gas system developed by Niemet and Selker (2001) and Model NW-A for water/NAPL system developed by Zhang et al. (2014) are applied for the calculation of fluid saturation in the two experiments, respectively. The gas injection experiments show that the gas moves upward in the irregular channels, piling up beneath the low permeability lenses and starting lateral movement. Bypassing the lenses, the gas moves upward and forms continuous distribution in the top of the sandbox. The faster of gas injects, the wider of gas migration will be. The DNAPL infiltration experiment shows that TCE mainly moves downward as the influence of gravity, stopping vertical infiltration when reaching the low permeability lenses because of its failure to overcome the capillary pressure. Then, TCE accumulates on the surface and starts transverse movement. Bypassing the

  3. Thermal non equilibrium in two phase flow

    International Nuclear Information System (INIS)

    Twenty eight reports presented in the 7th Eurotherm seminar are contained in this publication. They cover the main aspects of the thermodynamics in relation to nuclear systems or having reference to them

  4. SINGLE-PHASE AND TWO-PHASE SECONDARY COOLANTS: SIMULATION AND EVALUATION OF THEIR THERMOPHYSICAL PROPERTIES

    Directory of Open Access Journals (Sweden)

    Pedro Samuel Gomes Medeiros

    2011-09-01

    Full Text Available This paper makes a comparative analysis of the thermophysical properties of ice slurry with conventional single-phase secondary fluids used in thermal storage cooling systems. The ice slurry is a two-phase fluid consisting of water, antifreeze and ice crystals. It is a new technology that has shown great energy potential. In addition to transporting energy as a heat transfer fluid, it has thermal storage properties due to the presence of ice, storing coolness by latent heat of fusion. The single-phase fluids analyzed are water-NaCl and water-propylene glycol solutions, which also operate as carrier fluids in ice slurry. The presence of ice changes the thermophysical properties of aqueous solutions and a number of these properties were determined: density, thermal conductivity and dynamic viscosity. Data were obtained by software simulation. The results show that the presence of 10% by weight of ice provides a significant increase in thermal conductivity and dynamic viscosity, without causing changes in density. The rheological behavior of ice slurries, associated with its high viscosity, requires higher pumping power; however, this was not significant because higher thermal conductivity allows a lower mass flow rate without the use of larger pumps. Thus, the ice slurry ensures its high potential as a secondary fluid in thermal storage cooling systems, proving to be more efficient than single-phase secondary fluids.

  5. Flooding in counter-current two-phase flow

    International Nuclear Information System (INIS)

    Flooding is a phenomenon which is best described as the transition from counter-current to co-current flow. Early notice was taken of this phenomenon in the chemical engineering industry. Flooding also plays an important role in the field of two-phase heat transfer since it is a limit for many systems involving counter-current flow. Practical applications of flooding limited processes include wickless thermosyphons and the emergency core cooling system (ECCS) of pressurized water nuclear reactors. The phenomenon of flooding also is involved in the behavior of nuclear reactor core materials during severe accident conditions where flooding is one of the mechanisms governing the motion of the molten fuel pin cladding

  6. New concept of analytical method for two-phase flow

    International Nuclear Information System (INIS)

    The authors are developing a new analytical method for vertical upward two-phase flow based on a concept that two-phase flow with minimum pressure energy consumption rate is the most stable and easily flowable two-phase flow for the given boundary conditions and, thus, such two-phase flow should be realized actually. Although this concept is applied basically one-dimensionally in the analytical method, gravity convection effect due to density difference between liquid film on the channel wall and two-phase flow core in the central region of the channel is taken into account through a two-dimensional turbulent flow analysis. An air-water two-phase flow experiment was performed to verify the proposed analytical method. In the present paper, results of the experimental analysis with the proposed method are reported. (author)

  7. A bi-directional two-phase/two-phase heat exchanger

    Science.gov (United States)

    Ku, Jentung; Ottenstein, Laura

    1993-01-01

    This paper describes the design and test of a heat exchanger that transfers heat from one two-phase thermal loop to another with very small drops in temperature and pressure. The heat exchanger condenses the vapor in one loop while evaporating the liquid in the other without mixing of the condensing and evaporating fluids. The heat exchanger is bidirectional in that it can transfer heat in reverse, condensing on the normally evaporating side and vice versa. It is fully compatible with capillary pumped loops and mechanically pumped loops. Test results verified that performance of the heat exchanger met the design requirements. It demonstrated a heat transfer rate of 6800 watts in the normal mode of operation and 1000 watts in the reverse mode with temperature drops of less than 5 C between two thermal loops.

  8. Design and experiment of household biogas system in alpine region based on two-phase anaerobic fermentation%高寒地区两相厌氧户用沼气系统设计与试验

    Institute of Scientific and Technical Information of China (English)

    孙勇; 李文哲; 张鸿琼

    2012-01-01

    摘要;针对高寒地区农村户用沼气发酵周期过长、产气量少的状况,该文提出并设计了适用于高寒地区农村户用的两相厌氧发酵装置,通过确立合理的工艺方案,控制两相厌氧发酵中产酸相、料液温度和pH值、水力滞留时间等因素,探讨了在哈尔滨地区最寒冷季节,所设计的新型农村户用沼气发酵装置产气量与维持发酵罐体内料液温度所消耗沼气量之间的关系.结果表明:基于两相厌氧发酵的高寒地区高效户用沼气发酵装置最高产气率为1.35m3/(m3·d),是传统沼气池产气率( 0.35 m3/(m3·d))的4倍.冬季1月份日均结余4.08 m3沼气量足以满足三口之家照明、炊事所需能源,实现高寒地区户用沼气全年正能输出,可以取代传统沼气池.该文研究成果为今后寒地户用沼气的发展提供技术支持和参考依据.%According to the problems of long fermentation period and low gas production in the alpine region, a two-phase anaerobic fermentation device was designed for rural household biogas production in the alpine region. The fermentation parameters such as acid production, temperature and pH value of feed and hydraulic retention time were controlled during two-phase anaerobic fermentation. The relationship between the quantity of produced biogas during fermentation and the quantity of consumed biogas to maintain the biogas slurry temperature in most cold season in Harbin was discussed. Results showed that the highest methan production was 1.35 m3/(m3d) using the two-phase anaerobic fermentation process, which was four times higher than the traditional process of 0.35 m3/(m3-d). There was 4.08 m3 daily balance biogas to satisfy lighting and cooking for three people family in January of winter, which could operate in alpine region year-round. In addition, the equipment structure is reasonable and perfect, which might replace the traditional digester. The research can provide a technical support

  9. 两相厌氧系统处理磺胺废水的试验研究%Study on Treatment of Sulfanilamide Wastewater by Two-Phase Anaerobic System

    Institute of Scientific and Technical Information of China (English)

    任南琪; 刘艳玲; 刘敏; 周雪飞; 李建政; 王爱杰

    2001-01-01

    高浓度有机酸性磺胺废水通过中和、稀释、两相厌氧处理及对所产甲烷的毒性检测结果表明,该废水对产酸菌和产甲烷菌都有毒害抑制作用,但经中和、用其他废水稀释7倍后可进行厌氧处理,同时提出了适宜处理磺胺废水的工艺流程。%Treatment of acidic sulfanilamide wastewater with high concentration of organic matter by neutralization,dilution and two-phase anaerobic treatment was reported.The toxicity to methanogenic bacteria was monitored to determine its feasibility for anaerobic bio-treatment.The results showed that the wastewater had toxic and inhibitory effect on both acidogenic bacteria and methanogenic bacteria,while it was suitable to be anaerobically treated with the dilution of 7 times after neutralized pretreatment.In addition,the corresponding treatment process was presented.

  10. Stability of stratified two-phase flows in horizontal channels

    CERN Document Server

    Barmak, Ilya; Ullmann, Amos; Brauner, Neima; Vitoshkin, Helen

    2016-01-01

    Linear stability of stratified two-phase flows in horizontal channels to arbitrary wavenumber disturbances is studied. The problem is reduced to Orr-Sommerfeld equations for the stream function disturbances, defined in each sublayer and coupled via boundary conditions that account also for possible interface deformation and capillary forces. Applying the Chebyshev collocation method, the equations and interface boundary conditions are reduced to the generalized eigenvalue problems solved by standard means of numerical linear algebra for the entire spectrum of eigenvalues and the associated eigenvectors. Some additional conclusions concerning the instability nature are derived from the most unstable perturbation patterns. The results are summarized in the form of stability maps showing the operational conditions at which a stratified-smooth flow pattern is stable. It is found that for gas-liquid and liquid-liquid systems the stratified flow with smooth interface is stable only in confined zone of relatively lo...

  11. Phase appearance or disappearance in two-phase flows

    CERN Document Server

    Cordier, Floraine; Kumbaro, Anela

    2011-01-01

    This paper is devoted to the treatment of specific numerical problems which appear when phase appearance or disappearance occurs in models of two-phase flows. Such models have crucial importance in many industrial areas such as nuclear power plant safety studies. In this paper, two outstanding problems are identified: first, the loss of hyperbolicity of the system when a phase appears or disappears and second, the lack of positivity of standard shock capturing schemes such as the Roe scheme. After an asymptotic study of the model, this paper proposes accurate and robust numerical methods adapted to the simulation of phase appearance or disappearance. Polynomial solvers are developed to avoid the use of eigenvectors which are needed in usual shock capturing schemes, and a method based on an adaptive numerical diffusion is designed to treat the positivity problems. An alternate method, based on the use of the hyperbolic tangent function instead of a polynomial, is also considered. Numerical results are presente...

  12. Equations of two-phase flow in spray chamber

    Institute of Scientific and Technical Information of China (English)

    李新禹; 张志红; 金星; 徐杰

    2009-01-01

    The downstream water-air heat and moisture transfer system in a moving coordinate was studied. The relationship between the diameter of the misted droplets and the spray pressure was determined. Based on the theory of the relative velocity,the two-phase flow mode of the spray chamber and the efficiency equation for heat and moisture exchange were established. Corrections were carried out for the efficiency equation with spray pressure of 157 kPa. The results show that the pressure plays an important part in determining the efficiency of heat and moisture exchange. When the spray pressure is less than 157 kPa,better coincidence is noticed between the theoretical analysis and the test results with the error less than 6%. Greater error will be resulted in the case when the spray pressure is beyond 157 kPa. After the correction treatment,the coincidence between the theoretical and the experimental results is greatly improved.

  13. Thirty-two phase sequences design with good autocorrelation properties

    Indian Academy of Sciences (India)

    S P Singh; K Subba Rao

    2010-02-01

    Polyphase Barker Sequences are finite length, uniform complex sequences; the magnitude of their aperiodic autocorrelation sidelobes are bounded by 1. Such sequences have been used in numerous real-world applications such as channel estimation, radar and spread spectrum communication. In this paper, thirty-two phase Barker sequences up to length 24 with an alphabet size of only 32 are presented. The sequences from length 25 to 289 have autocorrelation properties better than well-known Frank codes. Because of the complex structure the sequences are very difficult to detect and analyse by an enemy’s electronic support measures (ESMs). The synthesized sequences are promising for practical application to radar and spread spectrum communication systems. These sequences are found using the Modified Simulated Annealing Algorithm (MSAA). The convergence rate of the algorithm is good.

  14. Dynamics Coefficient for Two-Phase Soil Model

    Directory of Open Access Journals (Sweden)

    Wrana Bogumił

    2015-02-01

    Full Text Available The paper investigates a description of energy dissipation within saturated soils-diffusion of pore-water. Soils are assumed to be two-phase poro-elastic materials, the grain skeleton of which exhibits no irreversible behavior or structural hysteretic damping. Description of motion and deformation of soil is introduced as a system of equations consisting of governing dynamic consolidation equations based on Biot theory. Selected constitutive and kinematic relations for small strains and rotation are used. This paper derives a closed form of analytical solution that characterizes the energy dissipation during steady-state vibrations of nearly and fully saturated poro-elastic columns. Moreover, the paper examines the influence of various physical factors on the fundamental period, maximum amplitude and the fraction of critical damping of the Biot column. Also the so-called dynamic coefficient which shows amplification or attenuation of dynamic response is considered.

  15. Dynamics Coefficient for Two-Phase Soil Model

    Science.gov (United States)

    Wrana, Bogumił

    2015-02-01

    The paper investigates a description of energy dissipation within saturated soils-diffusion of pore-water. Soils are assumed to be two-phase poro-elastic materials, the grain skeleton of which exhibits no irreversible behavior or structural hysteretic damping. Description of motion and deformation of soil is introduced as a system of equations consisting of governing dynamic consolidation equations based on Biot theory. Selected constitutive and kinematic relations for small strains and rotation are used. This paper derives a closed form of analytical solution that characterizes the energy dissipation during steady-state vibrations of nearly and fully saturated poro-elastic columns. Moreover, the paper examines the influence of various physical factors on the fundamental period, maximum amplitude and the fraction of critical damping of the Biot column. Also the so-called dynamic coefficient which shows amplification or attenuation of dynamic response is considered.

  16. Correct numerical simulation of a two-phase coolant

    Science.gov (United States)

    Kroshilin, A. E.; Kroshilin, V. E.

    2016-02-01

    Different models used in calculating flows of a two-phase coolant are analyzed. A system of differential equations describing the flow is presented; the hyperbolicity and stability of stationary solutions of the system is studied. The correctness of the Cauchy problem is considered. The models' ability to describe the following flows is analyzed: stable bubble and gas-droplet flows; stable flow with a level such that the bubble and gas-droplet flows are observed under and above it, respectively; and propagation of a perturbation of the phase concentration for the bubble and gas-droplet media. The solution of the problem about the breakdown of an arbitrary discontinuity has been constructed. Characteristic times of the development of an instability at different parameters of the flow are presented. Conditions at which the instability does not make it possible to perform the calculation are determined. The Riemann invariants for the nonlinear problem under consideration have been constructed. Numerical calculations have been performed for different conditions. The influence of viscosity on the structure of the discontinuity front is studied. Advantages of divergent equations are demonstrated. It is proven that a model used in almost all known investigating thermohydraulic programs, both in Russia and abroad, has significant disadvantages; in particular, it can lead to unstable solutions, which makes it necessary to introduce smoothing mechanisms and a very small step for describing regimes with a level. This does not allow one to use efficient numerical schemes for calculating the flow of two-phase currents. A possible model free from the abovementioned disadvantages is proposed.

  17. Two-phase flow and heat transfer symposium-workshop. Proceedings of condensed papers

    International Nuclear Information System (INIS)

    Two-phase flow applications are found in a wide range of engineering systems, such as boiling water reactors, conventional steam boilers, evaporators of refrigeration systems, and evaporative and condensive heat exchangers in chemical and petroleum industries. Over the past two decades, two-phase flow instability problems have been a challenge to many investigators. Such instabilities could induce boiling crisis, disturb control systems and/or cause mechanical damage. It is important to be able to predict the conditions under which a two-phase flow system will perform without instability. Therefore, the understanding of two-phase flow phenomena is extremely important for the design, control and performance prediction of such systems. Because of the recent energy crisis, many other two-phase flow problems have also become important. Some of them are the modeling of the loss of coolant accident in pressurized water nuclear reactors, scaling up of fluidized bed reactors for converting coal to clean gaseous and liquid fuels, and design of heat exchangers for liquified natural gas, and design of heat exchangers for liquified natural gas. There is a need to provide researchers and engineers in this field with an opportunity to exchange their experience and ideas in order to assess the state-of-the-art of two-phase flow and heat transfer studies, and to establish a basis for identification of areas of future research and application. This symposium provides the latest information on the status of two-phase flow and heat transfer research, development and applications. It also establish a rational basis for identification of areas of two-phase flow and heat transfer for further research and application

  18. Extraction of Biomolecules Using Phosphonium-Based Ionic Liquids + K3PO4 Aqueous Biphasic Systems

    OpenAIRE

    Louros, Cláudia L. S.; Cláudio, Ana Filipa M.; Neves, Catarina M. S. S.; Freire, Mara G.; Marrucho, Isabel M.; Jérôme Pauly; Coutinho, João A. P.

    2010-01-01

    Aqueous biphasic systems (ABS) provide an alternative and efficient approach for the extraction, recovery and purification of biomolecules through their partitioning between two liquid aqueous phases. In this work, the ability of hydrophilic phosphonium-based ionic liquids (ILs) to form ABS with aqueous K3PO4 solutions was evaluated for the first time. Ternary phase diagrams, and respective tie-lines and tie-lines length, formed by distinct phosphonium-based ILs, water, and K3PO4 at 298 K, we...

  19. Two Phases of Coherent Structure Motions in Turbulent Boundary Layer

    Institute of Scientific and Technical Information of China (English)

    LIU Jian-Hua; JIANG Nan

    2007-01-01

    Two phases of coherent structure motion are acquired after obtaining conditional phase-averaged waveforms for longitudinal velocity of coherent structures in turbulent boundary layer based on Harr wavelet transfer. The correspondences of the two phases to the two processes (i.e. ejection and sweep) during a burst are determined.

  20. Inhibition Effect of Mace Extract Microemulsion on Vitamin C Photooxidation in Aqueous Systems

    Directory of Open Access Journals (Sweden)

    Hasbullah Hasbullah

    2014-01-01

    Full Text Available Photooxidation in food systems cause nutritional losses and produces undesirable flavor, toxic and color compounds, which make foods less acceptable or unacceptable to consumers. The objective of this research was to know the effectiveness of mace extract microemulsion to inhibit vitamin C photooxidation in aqueous systems. Aqueous food systems used are both beverage model system and apple juice beverage, where in each system enriched by 100 ppm vitamin C as substrate and 20 ppm erytrosin as photosensitiser. It is about one percent and two percent of microemulsion that contain mace extract of 0, 500 and 750 ppm were added into each of aqueous food system. Inhibition effect of mace extract microemulsion toward vitamin C photooxidation based on the rate of vitamin C degradation in aqueous food systems that illuminated by fluorescent light with 2000 lux intensity within eight hours. The result indicated the mace extract microemulsion has anti-photooxidation activity and ability to inhibit vitamin C photooxidation in aqueous systems.

  1. Radiation formation of colloidal silver particles in aqueous systems

    Energy Technology Data Exchange (ETDEWEB)

    Cuba, Vaclav [CTU in Prague, Faculty of Nuclear Sciences and Physical Engineering, Brehova 7, 115 19 Prague 1 (Czech Republic)], E-mail: vaclav.cuba@fjfi.cvut.cz; Nemec, Mojmir; Gbur, Tomas; John, Jan; Pospisil, Milan; Mucka, Viliam [CTU in Prague, Faculty of Nuclear Sciences and Physical Engineering, Brehova 7, 115 19 Prague 1 (Czech Republic)

    2010-04-15

    This paper reports on the formation of silver nanoparticles initiated by gamma and UV radiation in various aqueous solutions. Inorganic precursors were used for radiation and/or photochemical reduction of Ag{sup +} ions to a metallic form. The influence of various parameters on the nucleation and formation of colloid particles was studied. Attention was also focused on the composition of the irradiated solution. Aliphatic alcohols were used as scavengers of OH radicals and other oxidizing species. The influence of the stabilizers on the formation and stability of the nanoparticles was studied.

  2. Structural developments of turbulent two-phase flow in large pipes

    International Nuclear Information System (INIS)

    In connection with the thermohydraulic problems of two-phase flow that may be encountered under certain operating conditions in piping systems containing heat sources and sinks such as a CANDU reactor heat transport system, this study investigates some of the turbulent characteristics of both cocurrent air-water two-phase flow and single phase flow in large pipes with horizontal orientation. Pitot tubes together with hot film anemometry have been shown to be an adequate measurement system in turbulent dispersed two-phase flow. A practical semi-empirical formula has been developed to predict local mixture velocity as a function of differential head read by Pitot tube, local void fraction, flow pattern constant, gas-liquid properties, momentum transfer factor and two-phase flow quality. The structural developments of the dispersed mixture velocity was studied along a straight horizontal PVC run and expressed in terms of the radial distance and the pipeline length. A correlation is introduced to determine the local mixture velocity in terms of radial and streamwise distance, two-phase flow quality, gas and liquid densities. A similar correlation is presented to predict the local developments of the void fraction. In addition to those normalized correlations, hypothetical interpretations of the experienced phenonema are presented. It was found that the mixture velocity is significantly influenced by the volumetric mixing ratio of both phases. Conclusions are drawn in the special cases of turbulent single and two-phase flow

  3. Tsunami Generated by a Two-Phase Submarine Debris Flow

    Science.gov (United States)

    Pudasaini, S. P.

    2012-04-01

    The general two-phase debris flow model proposed by Pudasaini (2011) is employed to study subaerial and submarine debris flows, and the tsunami generated by the debris impact at lakes and oceans. The model includes several essential physical aspects, including Mohr-Coulomb plasticity for the solid stress, while the fluid stress is modelled as a solid volume fraction gradient enhanced non-Newtonian viscous stress. The generalized interfacial momentum transfer includes the viscous drag, buoyancy, and the virtual mass. The generalized drag covers both the solid-like and fluid-like contributions, and can be applied to linear to quadratic drags. Strong couplings exist between the solid and the fluid momentum transfer. The advantage of the real two-phase debris flow model over classical single-phase or quasi-two-phase models is that by considering the solid (and/or the fluid) volume fraction appropriately, the initial mass can be divided into several (even mutually disjoint) parts; a dry (landslide or rock slide), a fluid (water or muddy water; e.g., dams, rivers), and a general debris mixture material as needed in real flow simulations. This offers a unique and innovative opportunity within a single framework to simultaneously simulate (a) the sliding debris (or landslide), (b) the water lake or ocean, (c) the debris impact at the lake or ocean, (d) tsunami generation and propagation, (e) mixing and separation between the solid and the fluid phases, and (f) sediment transport and deposition process in the bathymetric surface. The new model is applied to two-phase subaerial and submarine debris flows. Benchmark numerical simulations reveal that the dynamics of the debris impact induced tsunamis are fundamentally different than the tsunami generated by pure rock avalanche and landslides. Special attention is paid to study the basic features of the debris impact to the mountain lakes or oceans. This includes the generation, amplification and propagation of the multiple

  4. Research of Characteristics of Gas-liquid Two-phase Pressure Drop in Microreactor

    Directory of Open Access Journals (Sweden)

    Li Dan

    2015-01-01

    Full Text Available With the research system of nitrogen and deionized water, this paper researches the pressure drop of gas-liquid two-phase flow in the circular microchannel with an inner diameter which is respectively 0.9mm and 0.5mm, analyzes the effect of microchannel diameter on gas-liquid two-phase frictional pressure drop in the microchannel reactor, and compares with the result of frictional pressure drop and the predicting result of divided-phase flow pattern. The result shows that, the gas-liquid two-phase frictional pressure drop in the microchannel significantly increases with the decreasing microchannel diameter; Lockhart-Martinelli relationship in divided-phase flow pattern can preferably predict the gas-liquid two-phase frictional pressure drop in the microchannel, but the Tabular constant needs to be corrected.

  5. Modeling two-phase flow in PEM fuel cell channels

    Science.gov (United States)

    Wang, Yun; Basu, Suman; Wang, Chao-Yang

    2008-05-01

    This paper is concerned with the simultaneous flow of liquid water and gaseous reactants in mini-channels of a proton exchange membrane (PEM) fuel cell. Envisaging the mini-channels as structured and ordered porous media, we develop a continuum model of two-phase channel flow based on two-phase Darcy's law and the M2 formalism, which allow estimate of the parameters key to fuel cell operation such as overall pressure drop and liquid saturation profiles along the axial flow direction. Analytical solutions of liquid water saturation and species concentrations along the channel are derived to explore the dependences of these physical variables vital to cell performance on operating parameters such as flow stoichiometric ratio and relative humility. The two-phase channel model is further implemented for three-dimensional numerical simulations of two-phase, multi-component transport in a single fuel-cell channel. Three issues critical to optimizing channel design and mitigating channel flooding in PEM fuel cells are fully discussed: liquid water buildup towards the fuel cell outlet, saturation spike in the vicinity of flow cross-sectional heterogeneity, and two-phase pressure drop. Both the two-phase model and analytical solutions presented in this paper may be applicable to more general two-phase flow phenomena through mini- and micro-channels.

  6. Modeling two-phase flow in PEM fuel cell channels

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yun; Basu, Suman; Wang, Chao-Yang [Electrochemical Engine Center (ECEC), and Department of Mechanical and Nuclear Engineering, The Pennsylvania State University, University Park, PA 16802 (United States)

    2008-05-01

    This paper is concerned with the simultaneous flow of liquid water and gaseous reactants in mini-channels of a proton exchange membrane (PEM) fuel cell. Envisaging the mini-channels as structured and ordered porous media, we develop a continuum model of two-phase channel flow based on two-phase Darcy's law and the M{sup 2} formalism, which allow estimate of the parameters key to fuel cell operation such as overall pressure drop and liquid saturation profiles along the axial flow direction. Analytical solutions of liquid water saturation and species concentrations along the channel are derived to explore the dependences of these physical variables vital to cell performance on operating parameters such as flow stoichiometric ratio and relative humility. The two-phase channel model is further implemented for three-dimensional numerical simulations of two-phase, multi-component transport in a single fuel-cell channel. Three issues critical to optimizing channel design and mitigating channel flooding in PEM fuel cells are fully discussed: liquid water buildup towards the fuel cell outlet, saturation spike in the vicinity of flow cross-sectional heterogeneity, and two-phase pressure drop. Both the two-phase model and analytical solutions presented in this paper may be applicable to more general two-phase flow phenomena through mini- and micro-channels. (author)

  7. Research on one-dimensional two-phase flow

    International Nuclear Information System (INIS)

    In Part I the fundamental form of the hydrodynamic basic equations for a one-dimensional two-phase flow (two-fluid model) is described. Discussions are concentrated on the treatment of phase change inertial force terms in the equations of motion and the author's equations of motion which have a remarkable uniqueness on the following three points. (1) To express force balance of unit mass two-phase fluid instead of that of unit volume two-phase fluid. (2) To pick up the unit existing mass and the unit flowing mass as the unit mass of two-phase fluid. (3) To apply the kinetic energy principle instead of the momentum low in the evaluation of steady inertial force term. In these three, the item (1) is for excluding a part of momentum change or kinetic energy change due to mass change of the examined part of fluid, which is independent of force. The item (2) is not to introduce a phenomenological physical model into the evaluation of phase change inertial force term. And the item (3) is for correctly applying the momentum law taking into account the difference of representative velocities between the main flow fluid (vapor phase or liquid phase) and the phase change part of fluid. In Part II, characteristics of various kinds of high speed two-phase flow are clarified theoretically by the basic equations derived. It is demonstrated that the steam-water two-phase critical flow with violent flashing and the airwater two-phase critical flow without phase change can be described with fundamentally the same basic equations. Furthermore, by comparing the experimental data from the two-phase critical discharge test and the theoretical prediction, the two-phase discharge coefficient, CD, for large sharp-edged orifice is determined as the value which is not affected by the experimental facility characteristics, etc. (author)

  8. Dynamic Modeling of Phase Crossings in Two-Phase Flow

    DEFF Research Database (Denmark)

    Madsen, Søren; Veje, Christian; Willatzen, Morten

    2012-01-01

    Two-phase flow and heat transfer, such as boiling and condensing flows, are complicated physical phenomena that generally prohibit an exact solution and even pose severe challenges for numerical approaches. If numerical solution time is also an issue the challenge increases even further. We present...... of the variables and are usually very slow to evaluate. To overcome these challenges, we use an interpolation scheme with local refinement. The simulations show that the method handles crossing of the saturation lines for both liquid to two-phase and two-phase to gas regions. Furthermore, a novel result obtained...

  9. Tunable two-phase coexistence in half-doped manganites

    Indian Academy of Sciences (India)

    P Chaddah; A Banerjee

    2008-02-01

    We discuss our very interesting experimental observation that the low-temperature two-phase coexistence in half-doped manganites is multi-valued (at any field) in that we can tune the coexisting antiferromagnetic-insulating (AF-I) and the ferromagnetic-metallic (FM-M) phase fractions by following different paths in (; ) space. We have shown experimentally that the phase fraction, in this two-phase coexistence, can take continuous infinity of values. All but one of these are metastable, and two-phase coexistence is not an equilibrium state.

  10. What types of investors generate the two-phase phenomenon?

    Science.gov (United States)

    Ryu, Doojin

    2013-12-01

    We examine the two-phase phenomenon described by Plerou, Gopikrishnan, and Stanley (2003) [1] in the KOSPI 200 options market, one of the most liquid options markets in the world. By analysing a unique intraday dataset that contains information about investor type for each trade and quote, we find that the two-phase phenomenon is generated primarily by domestic individual investors, who are generally considered to be uninformed and noisy traders. In contrast, our empirical results indicate that trades by foreign institutions, who are generally considered informed and sophisticated investors, do not exhibit two-phase behaviour.

  11. Passive Two-Phase Cooling of Automotive Power Electronics: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Moreno, G.; Jeffers, J. R.; Narumanchi, S.; Bennion, K.

    2014-08-01

    Experiments were conducted to evaluate the use of a passive two-phase cooling strategy as a means of cooling automotive power electronics. The proposed cooling approach utilizes an indirect cooling configuration to alleviate some reliability concerns and to allow the use of conventional power modules. An inverter-scale proof-of-concept cooling system was fabricated, and tests were conducted using the refrigerants hydrofluoroolefin HFO-1234yf and hydrofluorocarbon HFC-245fa. Results demonstrated that the system can dissipate at least 3.5 kW of heat with 250 cm3 of HFC-245fa. An advanced evaporator design that incorporates features to improve performance and reduce size was conceived. Simulation results indicate its thermal resistance can be 37% to 48% lower than automotive dual side cooled power modules. Tests were also conducted to measure the thermal performance of two air-cooled condensers--plain and rifled finned tube designs. The results combined with some analysis were then used to estimate the required condenser size per operating conditions and maximum allowable system (i.e., vapor and liquid) temperatures.

  12. Simulation of two-phase flows by domain decomposition

    International Nuclear Information System (INIS)

    This thesis deals with numerical simulations of compressible fluid flows by implicit finite volume methods. Firstly, we studied and implemented an implicit version of the Roe scheme for compressible single-phase and two-phase flows. Thanks to Newton method for solving nonlinear systems, our schemes are conservative. Unfortunately, the resolution of nonlinear systems is very expensive. It is therefore essential to use an efficient algorithm to solve these systems. For large size matrices, we often use iterative methods whose convergence depends on the spectrum. We have studied the spectrum of the linear system and proposed a strategy, called Scaling, to improve the condition number of the matrix. Combined with the classical ILU pre-conditioner, our strategy has reduced significantly the GMRES iterations for local systems and the computation time. We also show some satisfactory results for low Mach-number flows using the implicit centered scheme. We then studied and implemented a domain decomposition method for compressible fluid flows. We have proposed a new interface variable which makes the Schur complement method easy to build and allows us to treat diffusion terms. Using GMRES iterative solver rather than Richardson for the interface system also provides a better performance compared to other methods. We can also decompose the computational domain into any number of sub-domains. Moreover, the Scaling strategy for the interface system has improved the condition number of the matrix and reduced the number of GMRES iterations. In comparison with the classical distributed computing, we have shown that our method is more robust and efficient. (author)

  13. Particle modulations to turbulence in two-phase round jets

    Institute of Scientific and Technical Information of China (English)

    Bing Wang; Huiqiang Zhang; Yi Liu; Xiaofen Yan; Xilin Wang

    2009-01-01

    The particle modulations to turbulence in round jets were experimentally studied by means of two-phase velocity measurements with Phase Doppler Anemometer (PDA). Laden with very large particles, no significant attenuations of turbulence intensities were measured in the far-fields, due to small two-phase slip velocities and particle Reynolds number. The gas-phase turbulence is enhanced by particles in the near-fields, but it is significantly attenuated by the small particles in the far-fields. The smaller particles have a more profound effect on the attenuation of turbulence intensities. The enhancements or attenuations of turbulence intensities in the far-fields depends on the energy production, transport and dissipation mechanisms between the two phases, which are determined by the particle prop-erties and two-phase velocity slips. The non-dimensional parameter CTI is introduced to represent the change of turbulence intensity.

  14. Two-phase repository construction concept: Engineering feasibility study

    International Nuclear Information System (INIS)

    As part of the Conceptual Design of a High Level Nuclear Waste Repository in Salt, and Engineering Feasibility Study was performed to evaluate the validity of the proposed two-phase repository construction concept as described in the Mission Plan. As a result of this study, the two-phase repository construction concept can be considered valid. The uncertainty associated with the site-related permitting and licensing process remains the major element of risk to the program schedule. With the application of the two-phase approach, surface and subsurface construction activities can be removed from the critical path. For this study, the Davis Canyon, Utah site was used. The study includes preliminary designs of the two-phase repository, surface and subsurface layouts, an overall integrated schedule, and cost estimates and evaluations regarding schedule and technical issues. 4 refs., 19 figs., 21 tabs

  15. Transient two-phase performance of LOFT reactor coolant pumps

    International Nuclear Information System (INIS)

    Performance characteristics of Loss-of-Fluid Test (LOFT) reactor coolant pumps under transient two-phase flow conditions were obtained based on the analysis of two large and small break loss-of-coolant experiments conducted at the LOFT facility. Emphasis is placed on the evaluation of the transient two-phase flow effects on the LOFT reactor coolant pump performance during the first quadrant operation. The measured pump characteristics are presented as functions of pump void fraction which was determined based on the measured density. The calculated pump characteristics such as pump head, torque (or hydraulic torque), and efficiency are also determined as functions of pump void fractions. The importance of accurate modeling of the reactor coolant pump performance under two-phase conditions is addressed. The analytical pump model, currently used in most reactor analysis codes to predict transient two-phase pump behavior, is assessed

  16. Refrigeration. Two-Phase Flow. Flow Regimes and Pressure Drop

    DEFF Research Database (Denmark)

    Knudsen, Hans-Jørgen Høgaard

    2002-01-01

    The note gives the basic definitions used in two-phase flow. Flow regimes and flow regimes map are introduced. The different contributions to the pressure drop are stated together with an imperical correlation from the litterature....

  17. Gravity Independence of Microchannel Two-Phase Flow Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Most of the amassed two-phase flow and heat transfer knowledge comes from experiments conducted in Earth’s gravity. Space missions span varying gravity...

  18. Vapor Compressor Driven Hybrid Two-Phase Loop Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Phase I project successfully demonstrated the feasibility of the vapor compression hybrid two-phase loop (VCHTPL). The test results showed the high...

  19. Mixed Model for Silt-Laden Solid-Liquid Two-Phase Flows

    Institute of Scientific and Technical Information of China (English)

    唐学林; 徐宇; 吴玉林

    2003-01-01

    The kinetic theory of molecular gases was used to derive the governing equations for dense solid-liquid two-phase flows from a microscopic flow characteristics viewpoint by multiplying the Boltzmann equation for each phase by property parameters and integrating over the velocity space. The particle collision term was derived from microscopic terms by comparison with dilute two-phase flow but with consideration of the collisions between particles for dense two-phase flow conditions and by assuming that the particle-phase velocity distribution obeys the Maxwell equations. Appropriate terms from the dilute two-phase governing equations were combined with the dense particle collision term to develop the governing equations for dense solid-liquid turbulent flows. The SIMPLEC algorithm and a staggered grid system were used to solve the discretized two-phase governing equations with a Reynolds averaged turbulence model. Dense solid-liquid turbulent two-phase flows were simulated for flow in a duct. The simulation results agree well with experimental data.

  20. IMPROVED SUBGRID SCALE MODEL FOR DENSE TURBULENT SOLID-LIQUID TWO-PHASE FLOWS

    Institute of Scientific and Technical Information of China (English)

    TANG Xuelin; QIAN Zhongdong; WU Yulin

    2004-01-01

    The dense solid-phase governing equations for two-phase flows are obtained by using the kinetic theory of gas molecules. Assuming that the solid-phase velocity distributions obey the Maxwell equations, the collision term for particles under dense two-phase flow conditions is also derived.In comparison with the governing equations of a dilute two-phase flow, the solid-particle's governing equations are developed for a dense turbulent solid-liquid flow by adopting some relevant terms from the dilute two-phase governing equations. Based on Cauchy-Helmholtz theorem and Smagorinsky model,a second-order dynamic sub-grid-scale (SGS) model, in which the sub-grid-scale stress is a function of both the strain-rate tensor and the rotation-rate tensor, is proposed to model the two-phase governing equations by applying dimension analyses. Applying the SIMPLEC algorithm and staggering grid system to the two-phase discretized governing equations and employing the slip boundary conditions on the walls, the velocity and pressure fields, and the volumetric concentration are calculated. The simulation results are in a fairly good agreement with experimental data in two operating cases in a conduit with a rectangular cross-section and these comparisons imply that these models are practical.

  1. Stochastic modelling of two-phase flows including phase change

    International Nuclear Information System (INIS)

    Stochastic modelling has already been developed and applied for single-phase flows and incompressible two-phase flows. In this article, we propose an extension of this modelling approach to two-phase flows including phase change (e.g. for steam-water flows). Two aspects are emphasised: a stochastic model accounting for phase transition and a modelling constraint which arises from volume conservation. To illustrate the whole approach, some remarks are eventually proposed for two-fluid models. (authors)

  2. Unsteady flow analysis of a two-phase hydraulic coupling

    Science.gov (United States)

    Hur, N.; Kwak, M.; Lee, W. J.; Moshfeghi, M.; Chang, C.-S.; Kang, N.-W.

    2016-06-01

    Hydraulic couplings are being widely used for torque transmitting between separate shafts. A mechanism for controlling the transmitted torque of a hydraulic system is to change the amount of working fluid inside the system. This paper numerically investigates three-dimensional turbulent flow in a real hydraulic coupling with different ratios of charged working fluid. Working fluid is assumed to be water and the Realizable k-ɛ turbulence model together with the VOF method are used to investigate two-phase flow inside the wheels. Unsteady simulations are conducted using the sliding mesh technique. The primary wheel is rotating at a fixed speed of 1780 rpm and the secondary wheel rotates at different speeds for simulating different speed ratios. Results are investigated for different blade angles, speed ratios and also different water volume fractions, and are presented in the form of flow patterns, fluid average velocity and also torques values. According to the results, blade angle severely affects the velocity vector and the transmitted torque. Also in the partially-filled cases, air is accumulated in the center of the wheel forming a toroidal shape wrapped by water and the transmitted torque sensitively depends on the water volume fraction. In addition, in the fully-filled case the transmitted torque decreases as the speed ration increases and the average velocity associated with lower speed ratios are higher.

  3. Biogasification of solid wastes by two-phase anaerobic fermentation

    International Nuclear Information System (INIS)

    Municipal, industrial and agricultural solid wastes, and biomass deposits, cause large-scale pollution of land and water. Gaseous products of waste decomposition pollute the air and contribute to global warming. This paper describes the development of a two-phase fermentation system that alleviates methanogenic inhibition encountered with high-solids feed, accelerates methane fermentation of the solid bed, and captures methane (renewable energy) for captive use to reduce global warming. The innovative system consisted of a solid bed reactor packed with simulated solid waste at a density of 160 kg/m3 and operated with recirculation of the percolated culture (bioleachate) through the bed. A rapid onset of solids hydrolysis, acidification, denitrification and hydrogen gas formation was observed under these operating conditions. However, these fermentative reactions stopped at a total fatty acids concentration of 13,000 mg/l (as acetic) at pH 5, with a reactor head-gas composition of 75 percent carbon dioxide, 20 percent nitrogen, 2 percent hydrogen and 3 percent methane. Fermentation inhibition was alleviated by moving the bioleachate to a separate methane-phase fermenter, and recycling methanogenic effluents at pH 7 to the solid bed. Coupled operation of the two reactors promoted methanogenic conversion of the high-solids feed. (author)

  4. Uncertainty analysis of two-phase flow pressure drop calculations

    Energy Technology Data Exchange (ETDEWEB)

    Siqueira, Cezar A.M.; Costa, Bruno M.P.; Fonseca Junior, Roberto da; Gonalves, Marcelo de A.L. [PETROBRAS, Rio de Janeiro, RJ (Brazil)

    2004-07-01

    The simulation of multiphase flow in pipes is usually performed by petroleum engineers with two main purposes: design of new pipelines and production systems; diagnosis of flow assurance problems in existing systems. The tools used for this calculation are computer codes that use published pressure drop correlations developed for steady-state two-phase flow, such as Hagedorn-Brown, Beggs and Brill and others. Each one of these correlations is best suited for a given situation and the engineer must find out the best option for each particular case, based on his experience. In order to select the best correlation to use and to analyze the results of the calculation, the engineer must determine the reliability of computed values. The uncertainty of the computation is obtained by considering uncertainties of the correlation adopted, of the calculation algorithm and the input data. This paper proposes a method to evaluate the uncertainties of this type of calculation and presents an analysis of these uncertainties. The uncertainty analysis also allows the identification of the parameters that are more significant for the final uncertainty of the simulation. Therefore it makes possible to determine which are the input parameters that must be determined with higher accuracy and the ones that may have lower accuracy, without reducing the reliability of the results. (author)

  5. Two-phase air-water stratified flow measurement using ultrasonic techniques

    Science.gov (United States)

    Fan, Shiwei; Yan, Tinghu; Yeung, Hoi

    2014-04-01

    In this paper, a time resolved ultrasound system was developed for investigating two-phase air-water stratified flow. The hardware of the system includes a pulsed wave transducer, a pulser/receiver, and a digital oscilloscope. The time domain cross correlation method is used to calculate the velocity profile along ultrasonic beam. The system is able to provide velocities with spatial resolution of around 1mm and the temporal resolution of 200μs. Experiments were carried out on single phase water flow and two-phase air-water stratified flow. For single phase water flow, the flow rates from ultrasound system were compared with those from electromagnetic flow (EM) meter, which showed good agreement. Then, the experiments were conducted on two-phase air-water stratified flow and the results were given. Compared with liquid height measurement from conductance probe, it indicated that the measured velocities were explainable.

  6. Rank 0 invariant solutions of dynamics of two-phase medium

    Science.gov (United States)

    Panov, Alexandr

    2016-08-01

    A system of partial differential equations which describes dynamics of two-phase medium is considered. Lie algebra of symmetry group of this system was found. For some 4-dimensional subalgebras of invariant solutions is found. All other 4-dimensional subalgebras will give only partial invariant solutions of this system.

  7. Dynamic behavior of pipes conveying gas–liquid two-phase flow

    Energy Technology Data Exchange (ETDEWEB)

    An, Chen, E-mail: anchen@cup.edu.cn [Offshore Oil/Gas Research Center, China University of Petroleum-Beijing, Beijing 102249 (China); Su, Jian, E-mail: sujian@lasme.coppe.ufrj.br [Nuclear Engineering Program, COPPE, Universidade Federal do Rio de Janeiro, CP 68509, Rio de Janeiro 21941-972 (Brazil)

    2015-10-15

    Highlights: • Dynamic behavior of pipes conveying gas–liquid two-phase flow was analyzed. • The generalized integral transform technique (GITT) was applied. • Excellent convergence behavior and long-time stability were shown. • Effects of volumetric quality and volumetric flow rate on dynamic behavior were studied. • Normalized volumetric-flow-rate stability envelope of dynamic system was determined. - Abstract: In this paper, the dynamic behavior of pipes conveying gas–liquid two-phase flow was analytically and numerically investigated on the basis of the generalized integral transform technique (GITT). The use of the GITT approach in the analysis of the transverse vibration equation lead to a coupled system of second order differential equations in the dimensionless temporal variable. The Mathematica's built-in function, NDSolve, was employed to numerically solve the resulting transformed ODE system. The characteristics of gas–liquid two-phase flow were represented by a slip-ratio factor model that was devised and used for similar problems. Good convergence behavior of the proposed eigenfunction expansions is demonstrated for calculating the transverse displacement at various points of pipes conveying air–water two-phase flow. Parametric studies were performed to analyze the effects of the volumetric gas fraction and the volumetric flow rate on the dynamic behavior of pipes conveying air–water two-phase flow. Besides, the normalized volumetric-flow-rate stability envelope for the dynamic system was obtained.

  8. Study on Distribution Behavior of Human Serum Albumin in Aqueous Two-Phase System%人血清白蛋白在双水相法体系中的分配规律研究

    Institute of Scientific and Technical Information of China (English)

    刘俊果

    2013-01-01

    人血清白蛋白是一种重要的临床药用蛋白质.以PEG/(NH4)2SO4双水相体系萃取分离人血清白蛋白,探索人血清白蛋白在双水相体系中的分配规律.结果表明,人血清白蛋白在双水相体系中的分配系数与萃取率均随着PEG分子量的增大而增大;随PEG和(NH4)2SO4浓度的增加而增加,当PEG为19.53%、(NH4)2SO4为14.07%时达到最大;但若持续增大各相的浓度,其分配系数与萃取率又会下降;随着体系中外加盐NaC1浓度的增加而增加,在NaC1浓度为10%时达到最大.

  9. ENZYMATIC SYNTHESIS OF CEPHALEXIN INTEGRATED WITH AQUEOUS TWO-PHASE SYSTEMS%酶法合成头孢氨苄的反应-双水相萃取耦合过程

    Institute of Scientific and Technical Information of China (English)

    朱建航; 魏东芝; 曹学君; 袁中一

    2003-01-01

    应用聚乙二醇(PEG)/硫酸镁双水相体系(ATPS)进行了酶法合成头孢氨苄的反应-双水相萃取的耦合过程研究.通过考察头孢氨苄、苯甘氨酸甲酯和7-氨基脱乙酰氧基头孢烷酸(7-ADCA)在ATPS中的分配行为建立了一个含20%(质量)PEG 400和12%(质量)硫酸镁的ATPS,在此体系中头孢氨苄的分配系数为6.7,苯甘氨酸甲酯的分配系数为1.5,7-ADCA的分配系数为1.2,且青霉素酰化酶的分配系数小于0.01.底物、产物以及催化剂的分配特性有利于构建双水相体系应用于酶法合成头孢氨苄的反应-双水相萃取的耦合过程.对此双水相体系中青霉素酰化酶的稳定性研究表明催化剂亦适合此体系的构建.进而将此体系应用于头孢氨苄酶法合成,产率为60%左右,相对水相体系20%左右的产率取得了较好的结果.

  10. Stability of stratified two-phase flows in horizontal channels

    Science.gov (United States)

    Barmak, I.; Gelfgat, A.; Vitoshkin, H.; Ullmann, A.; Brauner, N.

    2016-04-01

    Linear stability of stratified two-phase flows in horizontal channels to arbitrary wavenumber disturbances is studied. The problem is reduced to Orr-Sommerfeld equations for the stream function disturbances, defined in each sublayer and coupled via boundary conditions that account also for possible interface deformation and capillary forces. Applying the Chebyshev collocation method, the equations and interface boundary conditions are reduced to the generalized eigenvalue problems solved by standard means of numerical linear algebra for the entire spectrum of eigenvalues and the associated eigenvectors. Some additional conclusions concerning the instability nature are derived from the most unstable perturbation patterns. The results are summarized in the form of stability maps showing the operational conditions at which a stratified-smooth flow pattern is stable. It is found that for gas-liquid and liquid-liquid systems, the stratified flow with a smooth interface is stable only in confined zone of relatively low flow rates, which is in agreement with experiments, but is not predicted by long-wave analysis. Depending on the flow conditions, the critical perturbations can originate mainly at the interface (so-called "interfacial modes of instability") or in the bulk of one of the phases (i.e., "shear modes"). The present analysis revealed that there is no definite correlation between the type of instability and the perturbation wavelength.

  11. Mechanisms for two phase flow in porous media

    International Nuclear Information System (INIS)

    For a better understanding of transport mechanisms in soil for a system with two phases of immiscible liquids the physics of porous media gives again important contributions. In this report, the considerations mainly concentrate on horizontal transport. Our approach is based on the similarity solution of the transport equation which reduces a given nonlinear partial differential equation (PDE) to an ordinary differential equation (ODE). It can be seen, how dimensionless similarity solutions of the ODE depend, in addition to the similarity variable, on two parameters: - the capillary number Nc, giving the ratio of capillary forces and viscous forces, and - the ratio of the viscosities of the two liquid phases. It is shown, under which conditions different mechanisms of transport are to be expected, such as - a completely stable displacement or - an unstable displacement, related to viscous fingering (DLA, Diffusion Limited Aggregation) or to capillary fingering (IP, Invasion Percolation). These mechanisms are also strongly dependent on certain critical exponents (characteristic for DLA or IP). These relations are discussed in our report. Again, for some regions of saturation, mechanisms of displacement are either clearly dominated - by imbibition (e.g. water pushing oil) or - by drain (e.g. oil pushing water). Some of the results are also transformed again from the similarity solution of the ODE to a solution of the PDE (with space- and time coordinates). It is seen, that even with this somewhat simplified approach, we obtain a considerable spectrum of mechanisms. (orig.)

  12. Pressure transient analysis of two-phase flow problems

    Energy Technology Data Exchange (ETDEWEB)

    Chu, W.C.; Reynolds, A.C.; Raghavan, R.

    1986-04-01

    This paper considers the analysis of pressure drawdown and buildup data for two-phase flow problems. Of primary concern is the analysis of data influenced by saturation gradients that exist within the reservoir. Wellbore storage effects are assumed to be negligible. The pressure data considered are obtained from a two-dimensional (2D) numerical coning model for an oil/water system. The authors consider constant-rate production followed by a buildup period and assume that the top, bottom, and outer boundaries of the reservoir are sealed. First, they consider the case where the producing interval is equal to the total formation thickness. Second, they discuss the effect of partial penetration. In both cases, they show that average pressure can be estimated by the Matthews-Brons-Hazebroek method and consider the computation of the skin factor. They also show that a reservoir limit test can estimate reservoir PV only if the total mobility adjacent to the wellbore does not vary with time.

  13. 批量到达的、具有两种服务阶段和服务中断的重试排队系统的适定性%Well-Posedness of the Batch Arrival Retrial Queueing System with Two Phases of Service and Service Interruption

    Institute of Scientific and Technical Information of China (English)

    艾合买提·卡斯木; 艾尼·吾甫尔

    2012-01-01

    By using the Hille-Yosida theorem, the Phillips theorem and Fattorini theorem we prove that the batch arrival retrial queueing system with two phases of service and service interruption has a unique positive time-dependent solution which satisfies probability condition.%运用Hille-Yosida定理,Phillips定理与Fattorini定理证明批量到达、具有两种服务阶段和服务中断的重试排队系统存在唯一的、非负的、满足概率性质的时间依赖解.

  14. Performance of a passive emergency heat removal system of advanced reactors in two-phase flow and with high concentration of non-condensable; Atuacao de um sistema passivo de remocao de calor de emergencia de reatores avancados em escoamento bifasico e com alta concentracao de nao-condensaveis

    Energy Technology Data Exchange (ETDEWEB)

    Macedo, Luiz Alberto

    2008-07-01

    The research and the development of passive emergency cooling systems are necessary for the new generation of thermo-nuclear systems. Some basic information on the operation of these systems require the research of some relative processes to the natural circulation, mainly in conditions of two-phase flow involving processes of condensation in the presence of non-condensable gases, because many found situations are new. The experimental facility called Bancada de Circulacao Natural (BCN) was used for the realization of tests with diverse concentrations of non-condensable and power levels. The non-condensable gas present in the circuit decreases the rate of heat transfer for the secondary of the heat exchanger, determining low efficiency of the heat exchanger. High concentration of non-condensable in the vapor condensation, determines negative pressure, and cause the inversion of the flow in the circuit. The initial concentration of non-condensable and the geometry of the circuit, in the inlet of the heat exchanger, determines the establishment of transitory with two-phase flow. The BCN was performed with the computational code of Analysis of Accidents and Thermal-Hydraulics RELAP5/MOD 3.3 and, the calculated values had been compared with the experimental data, presenting good agreement for small non-condensable concentrations. The values calculated for high concentrations of non-condensable had been satisfactory after the circuit to have reached the temperature of saturation in the electric heater. (author)

  15. Biocompatibility of low molecular weight polymers for two-phase partitioning bioreactors.

    Science.gov (United States)

    Harris, Jesse; Daugulis, Andrew J

    2015-12-01

    Two phase partitioning bioreactors (TPPBs) improve the efficiency of fermentative processes by limiting the exposure of microorganisms to toxic solutes by sequestering them into a non-aqueous phase (NAP). A potential limitation of this technology, when using immiscible organic solvents as the NAP, is the cytoxicity that these materials may exert on the microbes. An improved TPPB configuration is one in which polymeric NAPs are used to replace organic solvents in order to take advantage of their low cost, improved handling qualities, and biocompatibility. A recent study has shown that low molecular weight polymers may confer improved solute uptake relative to high molecular weight polymers (i.e., have higher partition coefficients), but it is unknown whether sufficiently low molecular weight polymers may inhibit cell growth. This study has investigated the biocompatibility of a range of low molecular weight polymers, and compared trends in biocompatibility to the well-established "critical log P" concept. This was achieved by determining the biocompatibility of polypropylene glycol polymers over a molecular weight (MW) range of 425-4,000 to Saccharomyces cerevisiae and Pseudomonas putida, two organisms which have been previously used in TPPB systems. The lower MW polymers were shown to have lower average log P values, and showed more cytotoxicity than polymers of the same structure but with higher molecular weight. Since polymers are generally polydisperse (i.e., polymer samples contain a distribution of MWs), removal of the lower MW fractions via water washing was found to result in improved polymer biocompatibility. These results suggest that the critical log P concept remains useful for describing the toxicity of polymeric substances of different MWs, although it is complicated by the presence of the low MW fractions in the polymers arising from polydispersity.

  16. Characterizing dynamic hysteresis and fractal statistics of chaotic two-phase flow and application to fuel cells

    Science.gov (United States)

    Burkholder, Michael B.; Litster, Shawn

    2016-05-01

    In this study, we analyze the stability of two-phase flow regimes and their transitions using chaotic and fractal statistics, and we report new measurements of dynamic two-phase pressure drop hysteresis that is related to flow regime stability and channel water content. Two-phase flow dynamics are relevant to a variety of real-world systems, and quantifying transient two-phase flow phenomena is important for efficient design. We recorded two-phase (air and water) pressure drops and flow images in a microchannel under both steady and transient conditions. Using Lyapunov exponents and Hurst exponents to characterize the steady-state pressure fluctuations, we develop a new, measurable regime identification criteria based on the dynamic stability of the two-phase pressure signal. We also applied a new experimental technique by continuously cycling the air flow rate to study dynamic hysteresis in two-phase pressure drops, which is separate from steady-state hysteresis and can be used to understand two-phase flow development time scales. Using recorded images of the two-phase flow, we show that the capacitive dynamic hysteresis is related to channel water content and flow regime stability. The mixed-wettability microchannel and in-channel water introduction used in this study simulate a polymer electrolyte fuel cell cathode air flow channel.

  17. Investigation on two-phase flow instability in steam generator of integrated nuclear reactor

    Institute of Scientific and Technical Information of China (English)

    1996-01-01

    In the pressure range of 3-18MPa,high pressure steam-water two-phase flow density wave instability in vertical upward parallel pipes with inner diameter of 12mm is studied experimentally.The oscillation curves of two-phase flow instability and the effects of several parameters on the oscillation threshold of the system are obtained.Based on the small pertubation linearization method and the stability principles of automatic control system,a mathematical model is developed to predict the characteristics of density wave instability threshold.The predictions of the model are in good agreement with the experimental results.

  18. Determination of production-shipment policy using a two-phase algebraic approach

    Directory of Open Access Journals (Sweden)

    Huei-Hsin Chang

    2012-04-01

    Full Text Available The optimal production-shipment policy for end products using mathematicalmodeling and a two-phase algebraic approach is investigated. A manufacturing systemwith a random defective rate, a rework process, and multiple deliveries is studied with thepurpose of deriving the optimal replenishment lot size and shipment policy that minimisestotal production-delivery costs. The conventional method uses differential calculus on thesystem cost function to determine the economic lot size and optimal number of shipmentsfor such an integrated vendor-buyer system, whereas the proposed two-phase algebraicapproach is a straightforward method that enables practitioners who may not havesufficient knowledge of calculus to manage real-world systems more effectively.

  19. DRIFT: a network analysis computer program based on drift-flux model for two-phase flow

    International Nuclear Information System (INIS)

    A general description on various two-phase flow models used in the analysis of water reacter safety is given. An introduction to TRIFT, a one dimentional two-phase flow system analysis code based on nonequilibrium driftflux model, is presented. It also includes the calculation for a simple example and a summary on the characteristics of the code

  20. Comparison of two-phase and three-phase methanol synthesis processes

    NARCIS (Netherlands)

    van de Graaf, G.H; Beenackers, A.A C M

    1996-01-01

    A comparison is made between the ICI (two-phase) methanol synthesis process and a three-phase slurry process based on a multi-stage agitated reactor. The process calculations are based on a complete reactor system consisting of the reactor itself, a recycling system and a gas-liquid separator. The b

  1. Gas-liquid two-phase flow across a bank of micropillars

    Science.gov (United States)

    Krishnamurthy, Santosh; Peles, Yoav

    2007-04-01

    Adiabatic nitrogen-water two-phase flow across a bank of staggered circular micropillars, 100μm long with a diameter of 100μm and a pitch-to-diameter ratio of 1.5, was investigated experimentally for Reynolds number ranging from 5 to 50. Flow patterns, void fraction, and pressure drop were obtained, discussed, and compared to large scale as well as microchannel results. Two-phase flow patterns were determined by flow visualization, and a flow map was constructed as a function of gas and liquid superficial velocities. Significant deviations from conventional scale systems, with respect to flow patterns and trend lines, were observed. A unique flow pattern, driven by surface tension, was observed and termed bridge flow. The applicability of conventional scale models to predict the void fraction and two-phase frictional pressure drop was also assessed. Comparison with a conventional scale void fraction model revealed good agreement, but was found to be in a physically wrong form. Thus, a modified physically based model for void fraction was developed. A two-phase frictional multiplier was found to be a strong function of mass flux, unlike in previous microchannel studies. It was observed that models from conventional scale systems did not adequately predict the two-phase frictional multiplier at the microscale, thus, a modified model accounting for mass flux was developed.

  2. A Derivation of the Nonlocal Volume-Averaged Equations for Two-Phase Flow Transport

    Directory of Open Access Journals (Sweden)

    Gilberto Espinosa-Paredes

    2012-01-01

    Full Text Available In this paper a detailed derivation of the general transport equations for two-phase systems using a method based on nonlocal volume averaging is presented. The local volume averaging equations are commonly applied in nuclear reactor system for optimal design and safe operation. Unfortunately, these equations are limited to length-scale restriction and according with the theory of the averaging volume method, these fail in transition of the flow patterns and boundaries between two-phase flow and solid, which produce rapid changes in the physical properties and void fraction. The non-local volume averaging equations derived in this work contain new terms related with non-local transport effects due to accumulation, convection diffusion and transport properties for two-phase flow; for instance, they can be applied in the boundary between a two-phase flow and a solid phase, or in the boundary of the transition region of two-phase flows where the local volume averaging equations fail.

  3. Mathematical modeling of disperse two-phase flows

    CERN Document Server

    Morel, Christophe

    2015-01-01

    This book develops the theoretical foundations of disperse two-phase flows, which are characterized by the existence of bubbles, droplets or solid particles finely dispersed in a carrier fluid, which can be a liquid or a gas. Chapters clarify many difficult subjects, including modeling of the interfacial area concentration. Basic knowledge of the subjects treated in this book is essential to practitioners of Computational Fluid Dynamics for two-phase flows in a variety of industrial and environmental settings. The author provides a complete derivation of the basic equations, followed by more advanced subjects like turbulence equations for the two phases (continuous and disperse) and multi-size particulate flow modeling. As well as theoretical material, readers will discover chapters concerned with closure relations and numerical issues. Many physical models are presented, covering key subjects including heat and mass transfers between phases, interfacial forces and fluid particles coalescence and breakup, a...

  4. A mechanical erosion model for two-phase mass flows

    CERN Document Server

    Pudasaini, Shiva P

    2016-01-01

    Erosion, entrainment and deposition are complex and dominant, but yet poorly understood, mechanical processes in geophysical mass flows. Here, we propose a novel, process-based, two-phase, erosion-deposition model capable of adequately describing these complex phenomena commonly observed in landslides, avalanches, debris flows and bedload transport. The model is based on the jump in the momentum flux including changes of material and flow properties along the flow-bed interface and enhances an existing general two-phase mass flow model (Pudasaini, 2012). A two-phase variably saturated erodible basal morphology is introduced and allows for the evolution of erosion-deposition-depths, incorporating the inherent physical process including momentum and rheological changes of the flowing mixture. By rigorous derivation, we show that appropriate incorporation of the mass and momentum productions or losses in conservative model formulation is essential for the physically correct and mathematically consistent descript...

  5. Geomorphic and Aqueous Chemistry of a Portion of the Upper Rio Tinto System, Spain

    Science.gov (United States)

    Osburn, M. R.; Fernandez-Remolar, D. C.; Arvidson, R. E.; Morris, R. V.; Ming, D.; Prieto-Ballesteros, O.; Amils, R.; Stein, T. C.; Heil-Chapdelaine, V.; Friedlander, L. R.; Herndon, B.; Marlow, J.; Rosenberg, S.; Scherpker, K.; Steiner, A.

    2007-01-01

    Observations from the two Mars rovers, Spirit and Opportunity, combined with discoveries of extensive hydrated sulfate deposits from OMEGA and CRISM show that aqueous deposition and alteration involving acidic systems and sulfate deposition has been a key contributor to the martian geologic record. Rio Tinto, Spain, provides a process model for formation of sulfates on Mars by evaporation of acidic waters within shallow fluvial pools, particularly during dry seasons. We present results from a detailed investigation of an upper portion of the Rio Tinto, focusing on geomorphology, clastic sediment transport, and acidic aqueous processes. We also lay out lessons-learned for under-standing sulfate formation and alteration on Mars.

  6. Modeling of vapor-liquid-solid equilibrium in gas - aqueous electrolyte systems

    DEFF Research Database (Denmark)

    Thomsen, Kaj; Rasmussen, Peter

    1999-01-01

    A thermodynamic model for the description of vapor-liquid-solid equilibria is introduced. This model is a combination of the extended UNIQUAC model for electrolytes and the Soave-Redlich-Kwong cubic equation of state. The model has been applied to aqueous systems containing ammonia and/or carbon...

  7. Impact of ligand protonation on higher-order metal complexation kinetics in aqueous systems

    NARCIS (Netherlands)

    Town, R.M.; Leeuwen, van H.P.

    2008-01-01

    The impact of ligand protonation on the complexation kinetics of higher-order complexes is quantitatively described. The theory is formulated on the basis of the usual situation for metal complex formation in aqueous systems in which the exchange of water for the ligand in the inner coordination sph

  8. Shock wave of vapor-liquid two-phase flow

    Institute of Scientific and Technical Information of China (English)

    Liangju ZHAO; Fei WANG; Hong GAO; Jingwen TANG; Yuexiang YUAN

    2008-01-01

    The shock wave of vapor-liquid two-phase flow in a pressure-gain steam injector is studied by build-ing a mathematic model and making calculations. The results show that after the shock, the vapor is nearly com-pletely condensed. The upstream Mach number and the volume ratio of vapor have a great effect on the shock. The pressure and Mach number of two-phase shock con-form to the shock of ideal gas. The analysis of available energy shows that the shock is an irreversible process with entropy increase.

  9. Multi-needle capacitance probe for non-conductive two-phase flows

    Science.gov (United States)

    Monrós-Andreu, G.; Martinez-Cuenca, R.; Torró, S.; Escrig, J.; Hewakandamby, B.; Chiva, S.

    2016-07-01

    Despite its variable degree of application, intrusive instrumentation is the most accurate way to obtain local information in a two-phase flow system, especially local interfacial velocity and local interfacial area parameters. In this way, multi-needle probes, based on conductivity or optical principles, have been extensively used in the past few decades by many researchers in two-phase flow investigations. Moreover, the signal processing methods used to obtain the time-averaged two-phase flow parameters in this type of sensor have been thoroughly discussed and validated by many experiments. The objective of the present study is to develop a miniaturized multi-needle probe, based on capacitance measurements applicable to a wide range of non-conductive two-phase flows and, thus, to extend the applicability of multi-needle sensor whilst also maintaining a signal processing methodology provided in the literature for conductivity probes. Results from the experiments performed assess the applicability of the proposed sensor measurement principle and signal processing method for the bubbly flow regime. These results also provide an insight into the sensor application for more complex two-phase flow regimes.

  10. Carbon nanohybrids used as catalysts and emulsifiers for reactions in biphasic aqueous/organic systems

    Institute of Scientific and Technical Information of China (English)

    Daniel E. Resasco

    2014-01-01

    This mini-review summarizes some novel aspects of reactions conducted in aqueous/organic emul-sions stabilized by carbon nanohybrids functionalized with catalytic species. Carbon nanohybrids represent a family of solid catalysts that not only can stabilize water-oil emulsions in the same fash-ion as Pickering emulsions, but also catalyze reactions at the liquid/liquid interface. Several exam-ples are discussed in this mini-review. They include (a) aldol condensation-hydrodeoxygenation tandem reactions catalyzed by basic (MgO) and metal (Pd) catalysts, respectively; (b) Fischer-Tropsch synthesis catalyzed by carbon-nanotube-supported Ru;and (c) emulsion polymerization of styrene for the production of conductive polymer composites. Conducting these reactions in emul-sion generates important advantages, such as increased liquid/liquid interfacial area that conse-quently means faster mass transfer rates of molecules between the two phases, effective separation of products from the reaction mixture by differences in the water-oil solubility, and significant changes in product selectivity that can be adjusted by modifying the emulsion characteristics.

  11. Simulation of Two-Phase Flow in Sloshing Tanks

    NARCIS (Netherlands)

    Luppes, Roel; Veldman, Arthur; Wemmenhove, Rik; Kuzmin, A

    2011-01-01

    The CFD simulation tool ComFLOW is applied to study the effect of tank motions on two-phase flow phenomena inside a sloshing tank. An improved VOF method is used to assure an accurate description of the fluid displacement. With a novel “gravity-consistent” density averaging method, spurious velociti

  12. Two-phase alkali-metal experiments in reduced gravity

    Energy Technology Data Exchange (ETDEWEB)

    Antoniak, Z.I.

    1986-06-01

    Future space missions envision the use of large nuclear reactors utilizing either a single or a two-phase alkali-metal working fluid. The design and analysis of such reactors require state-of-the-art computer codes that can properly treat alkali-metal flow and heat transfer in a reduced-gravity environment. A literature search of relevant experiments in reduced gravity is reported on here, and reveals a paucity of data for such correlations. The few ongoing experiments in reduced gravity are noted. General plans are put forth for the reduced-gravity experiments which will have to be performed, at NASA facilities, with benign fluids. A similar situation exists regarding two-phase alkali-metal flow and heat transfer, even in normal gravity. Existing data are conflicting and indequate for the task of modeling a space reactor using a two-phase alkali-metal coolant. The major features of past experiments are described here. Data from the reduced-gravity experiments with innocuous fluids are to be combined with normal gravity data from the two-phase alkali-metal experiments. Analyses undertaken here give every expectation that the correlations developed from this data base will provide a valid representation of alkali-metal heat transfer and pressure drop in reduced gravity.

  13. Thermalhydraulic instability analysis of a two phase natural circulation loop

    International Nuclear Information System (INIS)

    This work presents an analysis of a loop operating in natural circulation regime. Experiments were done in a rectangular closed circuit in one and two-phase flows. Numerical analysis were performed initially with the CIRNAT code and afterwards with RELAP5/MOD2. The limitations of CIRNAT were studied and new developments for this code are proposed. (author)

  14. TWO-PHASE EJECTOR of CARBON DIOXIDE HEAT PUMP CALCULUS

    Directory of Open Access Journals (Sweden)

    Sit B.M.

    2010-12-01

    Full Text Available It is presented the calculus of the two-phase ejector for carbon dioxide heat pump. The method of calculus is based on the method elaborated by S.M. Kandil, W.E. Lear, S.A. Sherif, and is modified taking into account entrainment ratio as the input for the calculus.

  15. Numerical simulation of two-phase flow in offshore environments

    NARCIS (Netherlands)

    Wemmenhove, Rik

    2008-01-01

    Numerical Simulation of Two-Phase Flow in Offshore Environments Rik Wemmenhove Weather conditions on full sea are often violent, leading to breaking waves and lots of spray and air bubbles. As high and steep waves may lead to severe damage on ships and offshore structures, there is a great need for

  16. Numerical simulation of two phase flows in heat exchangers

    International Nuclear Information System (INIS)

    The report presents globally the works done by the author in the thermohydraulic applied to nuclear reactors flows. It presents the studies done to the numerical simulation of the two phase flows in the steam generators and a finite element method to compute these flows. (author)

  17. Heat treatment method for two-phase stainless steel

    International Nuclear Information System (INIS)

    A two-phase stainless steel the toughness of which is reduced by exposure to a high temperature is kept at from 900degC to 1040degC to be solidified and then quenched. With such procedures, a δ-phase deposited in a ferrite phase can be eliminated to restore the toughness. In the solidification step, the two-phase stainless steel having a plate thickness of 1cm or less is kept for 15mins or more, and is kept for additional 5min on every increase of the thickness of 1cm, and then it is compulsorily cooled with water or air. In the heat treatment comprising such steps, a Cr-depleted layer of the welded portion of the two-phase stainless steel of reduced toughness is eliminated to restore an initial state thereby enabling to maintain the integrity of the welded portion. Since the δ-phase deposited in the ferrite phase can be eliminated by solid-solubilizing the two phase stainless steel of reduced toughness by induction heating, reduced toughness can be restored thereby enabling to keep the integrity. (T.M.)

  18. Orientation relationship representation in two-phase material

    OpenAIRE

    A. Góral; Jura, J.

    2008-01-01

    Purpose: Orientation characteristics determination, especially orientation relationship, in two-phase materialsis important in predicting the material properties. The possible orientation relationship representations werepresented and discussed in the paper.Design/methodology/approach: Mathematical formalisms of the quantitative texture and microtextureanalysis were applied.Findings: Various orientation characteristics, especially orientation relationship representation may be used inthe quan...

  19. Analysis of data obtained in two-phase flow tests of primary heat transport pumps

    International Nuclear Information System (INIS)

    This report analyzes data obtained in two-phase flow tests of primary heat transport pumps performed during the period 1980-1983. Phenomena which have been known to cause pump-induced flow oscillations in pressurized piping systems under two-phase conditions are reviewed and the data analyzed to determine whether any of the identified phenomena could have been responsible for the instabilities observed in those tests. Tentative explanations for the most severe instabilities are given based on those analyses. It is shown that suction pipe geometry probably plays an important role in promoting instabilities, so additional experiments to investigate the effect of suction pipe geometry on the stability of flow in a closed pipe loop under two-phase conditions are recommended

  20. Analytical solution of laminar-laminar stratified two-phase flows with curved interfaces

    International Nuclear Information System (INIS)

    The present study represents a complete analytical solution for laminar two-phase flows with curved interfaces. The solution of the Navier-Stokes equations for the two-phases in bipolar coordinates provides the 'flow monograms' describe the relation between the interface curvature and the insitu flow geometry when given the phases flow rates and viscosity ratios. Energy considerations are employed to construct the 'interface monograms', whereby the characteristic interfacial curvature is determined in terms of the phases insitu holdup, pipe diameter, surface tension, fluids/wall adhesion and gravitation. The two monograms are then combined to construct the system 'operational monogram'. The 'operational monogram' enables the determination of the interface configuration, the local flow characteristics, such as velocity profiles, wall and interfacial shear stresses distribution as well as the integral characteristics of the two-phase flow: phases insitu holdup and pressure drop

  1. Visualization and measurement of two-phase flow in tight rod bundle by neutron tomography

    International Nuclear Information System (INIS)

    Neutron tomography thermal-hydraulic measurement technique is originally developed based on the neutron radiography, computed tomography and two-phase flow measurement techniques. The purpose of the developing is to measure the void fraction distribution in the Reduced-Moderation Water Reactor which is a water-cooled breeder reactor designed by the JAERI as a future reactor. We have visualized and measured the void distribution of air/water two-phase flow and boiling flow in tight-lattice rod bundles. We used the research reactor JRR-3 as a neutron source. Three-dimensional data can be obtained in order to evaluate the numerical analysis codes. In this manuscript, the neutron tomography system, comparison between the reconstruction methods of computed tomography and examples of the measured two-phase flow data which was taken in the 7 rod bundle with a gap between rods of 1.0 mm. (author)

  2. Analytical solution of laminar-laminar stratified two-phase flows with curved interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Brauner, N.; Rovinsky, J.; Maron, D.M. [Tel-Aviv Univ. (Israel)

    1995-09-01

    The present study represents a complete analytical solution for laminar two-phase flows with curved interfaces. The solution of the Navier-Stokes equations for the two-phases in bipolar coordinates provides the `flow monograms` describe the relation between the interface curvature and the insitu flow geometry when given the phases flow rates and viscosity ratios. Energy considerations are employed to construct the `interface monograms`, whereby the characteristic interfacial curvature is determined in terms of the phases insitu holdup, pipe diameter, surface tension, fluids/wall adhesion and gravitation. The two monograms are then combined to construct the system `operational monogram`. The `operational monogram` enables the determination of the interface configuration, the local flow characteristics, such as velocity profiles, wall and interfacial shear stresses distribution as well as the integral characteristics of the two-phase flow: phases insitu holdup and pressure drop.

  3. Entropy analysis on non-equilibrium two-phase flow models

    Energy Technology Data Exchange (ETDEWEB)

    Karwat, H.; Ruan, Y.Q. [Technische Universitaet Muenchen, Garching (Germany)

    1995-09-01

    A method of entropy analysis according to the second law of thermodynamics is proposed for the assessment of a class of practical non-equilibrium two-phase flow models. Entropy conditions are derived directly from a local instantaneous formulation for an arbitrary control volume of a structural two-phase fluid, which are finally expressed in terms of the averaged thermodynamic independent variables and their time derivatives as well as the boundary conditions for the volume. On the basis of a widely used thermal-hydraulic system code it is demonstrated with practical examples that entropy production rates in control volumes can be numerically quantified by using the data from the output data files. Entropy analysis using the proposed method is useful in identifying some potential problems in two-phase flow models and predictions as well as in studying the effects of some free parameters in closure relationships.

  4. Problems of heat transfer and hydraulics of two-phase media

    CERN Document Server

    Kutateladze, S S

    1969-01-01

    Problems of Heat Transfer and Hydraulics of Two-Phase Media presents the theory of heat transfer and hydrodynamics. This book discusses the various aspects of heat transfer and the flow of two-phase systems. Organized into two parts encompassing 22 chapters, this book starts with an overview of the laws of similarity for heat transfer to or from a flowing liquid with various physical properties and allowed for variation in viscosity and thermal conductivity. This book then explores the general functional relationship that exists between viscosity and thermal conductivity for thermodynamically

  5. Position Control of Synchronous Motor Drive by Modified Adaptive Two-phase Sliding Mode Controller

    Institute of Scientific and Technical Information of China (English)

    Mohamed Said Sayed Ahmed; Ping Zhang; Yun-Jie Wu

    2008-01-01

    A modified adaptive two-phase sliding mode controller for the synchronous motor drive that is highly robust to uncertain-ties and external disturbances is proposed in this paper. The proposed controller uses two-phase sliding mode control (SMC) where the 1st phase mainly controls the system in steady states and disturbed states-it is a smoothing phase. The 2nd phase is used mainly in the case of disturbed states. Also, it is an autotuning phase and uses a simple adaptive algorithm to tune the gain of conventional variable structure control (VSC). The modified controller is useful in position control of a permanent magnet synchronous drive.

  6. Two-phase anaerobic digestion of coffee wet wastewater: Effect of recycle on anaerobic process performance

    OpenAIRE

    Yans Guardia Puebla; Suyén Rodríguez Pérez; Yennys Cuscó Varona; Janet Jiménez Hernández; Víctor Sánchez Girón

    2014-01-01

    The present work shows the results of the two-phase anaerobic digestion assessment for the treatment of coffee wet wastewater. The effect of recycle on the anaerobic digestion process was studied. Twooverall organic loading rate (OLR) values of 4,2 and 5,7 kgCOD·m -3 ·d -1 , with same overall hydraulic retention time (HRT) of 21,5 h was evaluated.In a two-phase system wereapplied two recycle rate of 0,4 and 1,0, of the effluent of an UASB-UAF methanogenic hybrid reactor towards an UASB acidog...

  7. Enhanced two phase flow in heat transfer systems

    Energy Technology Data Exchange (ETDEWEB)

    Tegrotenhuis, Ward E; Humble, Paul H; Lavender, Curt A; Caldwell, Dustin D

    2013-12-03

    A family of structures and designs for use in devices such as heat exchangers so as to allow for enhanced performance in heat exchangers smaller and lighter weight than other existing devices. These structures provide flow paths for liquid and vapor and are generally open. In some embodiments of the invention, these structures can also provide secondary heat transfer as well. In an evaporate heat exchanger, the inclusion of these structures and devices enhance the heat transfer coefficient of the evaporation phase change process with comparable or lower pressure drop.

  8. Ion mixing, hydration, and transport in aqueous ionic systems

    International Nuclear Information System (INIS)

    The enhancement effect on the ion mobility of fluoride (and that of chloride) in a polycationic system, as the chloride content increases, is shown to also exist in other more simple ionic systems with cations such as the cesium ion and an organic ammonium ion. As the chloride content increases, in addition to the finding that there is more unbound water associated with the cation, we also observe that the average lifetime of a hydrogen bond decreases. This change to the hydrogen bonds is correlated to significant changes to both the structural and dynamical properties of water. The more disordered water structure and faster water dynamics are hypothesized to be also responsible for the enhanced ion mobilities. Furthermore, when either the chloride content or hydration level is changed, the self-diffusion constant of each co-ion changes by almost the same factor, implying the existence of a single universal transport mechanism that determines ion mobilities

  9. Dissolution state of cellulose in aqueous systems. 2. Acidic solvents.

    Science.gov (United States)

    Alves, Luis; Medronho, Bruno; Antunes, Filipe E; Topgaard, Daniel; Lindman, Björn

    2016-10-20

    Cellulose is insoluble in water but can be dissolved in strong acidic or alkaline conditions. How well dissolved cellulose is in solution and how it organizes are key questions often neglected in literature. The typical low pH required for dissolving cellulose in acidic solvents limits the use of typical characterization techniques. In this respect, Polarization Transfer Solid State NMR (PT ssNMR) emerges as a reliable alternative. In this work, combining PT ssNMR, microscopic techniques and X-ray diffraction, a set of different acidic systems (phosphoric acid/water, sulfuric acid/glycerol and zinc chloride/water) is investigated. The studied solvent systems are capable to efficiently dissolve cellulose, although degradation occurs to some extent. PT ssNMR is capable to identify the liquid and solid fractions of cellulose, the degradation products and it is also sensitive to gelation. The materials regenerated from the acidic dopes were found to be highly sensitive to the solvent system and to the presence of amphiphilic additives in solution. PMID:27474617

  10. Extraction of Biomolecules Using Phosphonium-Based Ionic Liquids + K3PO4 Aqueous Biphasic Systems

    Directory of Open Access Journals (Sweden)

    Cláudia L. S. Louros

    2010-04-01

    Full Text Available Aqueous biphasic systems (ABS provide an alternative and efficient approach for the extraction, recovery and purification of biomolecules through their partitioning between two liquid aqueous phases. In this work, the ability of hydrophilic phosphonium-based ionic liquids (ILs to form ABS with aqueous K3PO4 solutions was evaluated for the first time. Ternary phase diagrams, and respective tie-lines and tie-lines length, formed by distinct phosphonium-based ILs, water, and K3PO4 at 298 K, were measured and are reported. The studied phosphonium-based ILs have shown to be more effective in promoting ABS compared to the imidazolium-based counterparts with similar anions. Moreover, the extractive capability of such systems was assessed for distinct biomolecules (including amino acids, food colourants and alkaloids. Densities and viscosities of both aqueous phases, at the mass fraction compositions used for the biomolecules extraction, were also determined. The evaluated IL-based ABS have been shown to be prospective extraction media, particularly for hydrophobic biomolecules, with several advantages over conventional polymer-inorganic salt ABS.

  11. Mineralogic controls on aqueous neptunium(V) concentrations in silicate systems

    Energy Technology Data Exchange (ETDEWEB)

    Alessi, Daniel S., E-mail: daniel.alessi@epfl.ch [Department of Civil Engineering and Geological Sciences, University of Notre Dame, 156 Fitzpatrick Hall, Notre Dame, IN 46556 (United States); Szymanowski, Jennifer E.S. [Department of Civil Engineering and Geological Sciences, University of Notre Dame, 156 Fitzpatrick Hall, Notre Dame, IN 46556 (United States); Forbes, Tori Z. [Department of Civil Engineering and Geological Sciences, University of Notre Dame, 156 Fitzpatrick Hall, Notre Dame, IN 46556 (United States); Department of Chemistry, University of Iowa, Room E331 CB, Iowa City, IA 52242 (United States); Quicksall, Andrew N. [Department of Civil Engineering and Geological Sciences, University of Notre Dame, 156 Fitzpatrick Hall, Notre Dame, IN 46556 (United States); Department of Civil and Environmental Engineering, Southern Methodist University, P.O. Box 750340, Dallas, TX 75275 (United States); Sigmon, Ginger E.; Burns, Peter C.; Fein, Jeremy B. [Department of Civil Engineering and Geological Sciences, University of Notre Dame, 156 Fitzpatrick Hall, Notre Dame, IN 46556 (United States)

    2013-02-15

    The presence of radioactive neptunium in commercially spent nuclear fuel is problematic due to its mobility in environmental systems upon oxidation to the pentavalent state. As uranium is the major component of spent fuel, incorporation of neptunium into resulting U(VI) mineral phases would potentially influence its release into environmental systems. Alternatively, aqueous neptunium concentrations may be buffered by solid phase Np{sub 2}O{sub 5}. In this study, we investigate both of these controls on aqueous neptunium(V) concentrations. We synthesize two uranyl silicates, soddyite, (UO{sub 2}){sub 2}SiO{sub 4}·2H{sub 2}O, and boltwoodite, (K, Na)(UO{sub 2})(SiO{sub 3}OH)·1.5H{sub 2}O, each in the presence of two concentrations of aqueous Np(V). Electron microscopy and electron diffraction analyses of the synthesized phases show that while significant neptunyl incorporation occurred into soddyite, the Np(V) in the boltwoodite systems largely precipitated as a secondary phase, Np{sub 2}O{sub 5(s)}. The release of Np(V) from each system into aqueous solution was measured for several days, until steady-state concentrations were achieved. Using existing solubility constants (K{sub sp}) for pure soddyite and boltwoodite, we compared predicted equilibrium aqueous U(VI) concentrations with the U(VI) concentrations released in the solubility experiments. Our experiments reveal that Np(V) incorporation into soddyite increases the concentration of aqueous U in equilibrium with the solid phase, perhaps via the formation of a metastable phase. In the mixed boltwoodite – Np{sub 2}O{sub 5(s)} system, the measured aqueous U(VI) activities are consistent with those predicted to be in equilibrium with boltwoodite under the experimental conditions, a result that is consistent with our conclusion that little Np(V) incorporation occurred into the boltwoodite. In the boltwoodite systems, the measured Np concentrations are likely controlled by the presence of Np{sub 2}O{sub 5

  12. Severe slugging in gas-liquid two-phase pipe flow

    NARCIS (Netherlands)

    Malekzadeh, R.

    2012-01-01

    transportation facilities. In an offshore oil and gas production facility, pipeline-riser systems are required to transport two-phase hydrocarbons from subsurface oil and gas wells to a central production platform. Severe slugs reaching several thousands pipe diameters may occur when transporting g

  13. A FINITE ELEMENT COLLOCATION METHOD FOR TWO-PHASE INCOMPRESSIBLE IMMISCIBLE PROBLEMS

    Institute of Scientific and Technical Information of China (English)

    Ma Ning

    2007-01-01

    Two-phase, incompressible, immiscible flow in porous media is governed by a coupled system of nonlinear partial differential equations. The pressure equation is elliptic,whereas the concentration equation is parabolic, and both are treated by the collocation scheme. Existence and uniqueness of solutions of the algorithm are proved. A optimal convergence analysis is given for the method.

  14. Geological pattern formation by growth and dissolution in aqueous systems

    Energy Technology Data Exchange (ETDEWEB)

    Paul Meakin

    2010-03-01

    Although many geological processes take place on time scales that are very long compared with the human experience, essentially all geological processes, fast or slow, are far from equilibrium processes. Surprisingly often, geological processes lead to the formation of quite simple and distinctive patterns, which hint at an underlying simplicity in many complex geological systems.. The ability to predict the seasons was critically important to early human society, and Halley’s prediction of the return of the comet that bears his name is still considered to be a scientific milestone. Spatial patterns have also attracted attention because of their aesthetic appeal, which depends in subtle ways on a combination of regularity and irregularity. In recent decades, rapid growth in the capabilities of digital computers has facilitated the simulation of pattern formation processes, and computer simulations have become an important tool for evaluating theoretical concepts and for scientific discovery. Computer technology in combination with other technologies such as high resolution digital cameras, scanning microprobes (atomic force microscopy AFM), confocal microscopy, and scanning tunneling microscopy (STM), for example) has facilitated the quantitative characterization of patterns over a wide range of scales and has enabled rapid advances in our ability to understand the links between large scale pattern formation and microscopic processes. The ability to quantitatively characterize patterns is important because it enables a more rigorous comparison between the predictions of computer models and real world patterns and their formation.In some cases, the idea that patterns with a high degree of regularity have simple origins appears to be justified, but in other cases, such as the formation of almost perfectly circular stone rings due to freeze-thaw cycles simple patterns appear to be the consequence of quite complex processes. In other cases, it has been shown that

  15. Aqueous two phase extraction of proteins: From molecular understanding to process development

    OpenAIRE

    Oelmeier, Stefan A

    2012-01-01

    A high throughput screening method was implemented and applied to an industrial separation task. Previously reported correlations between protein descriptors and distribution were evaluated. A new approach to screen ATPS for their industrial application was devised and put to use for the selection of ATPSs used in centrifugal partitioning chromatography. A new modeling approach based on molecular dynamics was set up. This approach was validated using single PEG molecules in solution.

  16. Investigations of two-phase flame propagation under microgravity conditions

    Science.gov (United States)

    Gokalp, Iskender

    2016-07-01

    Investigations of two-phase flame propagation under microgravity conditions R. Thimothée, C. Chauveau, F. Halter, I Gökalp Institut de Combustion, Aérothermique, Réactivité et Environnement (ICARE), CNRS, 1C Avenue de la Recherche Scientifique, 45071 Orléans Cedex 2, France This paper presents and discusses recent results on two-phase flame propagation experiments we carried out with mono-sized ethanol droplet aerosols under microgravity conditions. Fundamental studies on the flame propagation in fuel droplet clouds or sprays are essential for a better understanding of the combustion processes in many practical applications including internal combustion engines for cars, modern aircraft and liquid rocket engines. Compared to homogeneous gas phase combustion, the presence of a liquid phase considerably complicates the physico-chemical processes that make up combustion phenomena by coupling liquid atomization, droplet vaporization, mixing and heterogeneous combustion processes giving rise to various combustion regimes where ignition problems and flame instabilities become crucial to understand and control. Almost all applications of spray combustion occur under high pressure conditions. When a high pressure two-phase flame propagation is investigated under normal gravity conditions, sedimentation effects and strong buoyancy flows complicate the picture by inducing additional phenomena and obscuring the proper effect of the presence of the liquid droplets on flame propagation compared to gas phase flame propagation. Conducting such experiments under reduced gravity conditions is therefore helpful for the fundamental understanding of two-phase combustion. We are considering spherically propagating two-phase flames where the fuel aerosol is generated from a gaseous air-fuel mixture using the condensation technique of expansion cooling, based on the Wilson cloud chamber principle. This technique is widely recognized to create well-defined mono-size droplets

  17. Water transport in two-phase fuel cell microchannels

    Science.gov (United States)

    Lee, Eon Soo

    Many fuel cells contain small rectangular channels in which three of the channel walls are smooth, impermeable metal and the fourth wall is a porous gas-diffusion layer. The main function of the channels is to supply reactant gases through the porous layer to the reaction surface, but also to remove water formed by the electro-chemical reactions. Analysis of the two-phase flow through these channels is complicated by the fact that both gas and liquid can move through either the channel or the porous layer. This study presents the flow regime maps for the two-phase flow and a 1-D two-phase flow model for the frictional characteristics of the porous wall bounded channel flow. Experiments were performed on a straight 200 by 500 micron by 150 mm long rectangular channel. Three walls of the channel were machined into a solid piece of acrylic. One of the 500 micron wide walls was a commercial Toray carbon paper gas-diffusion layer (GDL) material held in place by a flat sheet of acrylic. Water was forced through the GDL layer from four evenly spaced holes in the flat acrylic piece. Two-phase flow regime maps were constructed from flow visualization in terms of a superficial gas velocity, JG and the superficial liquid velocity, JL at the channel exit between 0 velocities increased. The transition from plug flow generally occurs at a constant superficial gas velocity and a two-phase Weber number is proposed as an appropriate dimensionless parameter to characterize this transition. A one-dimensional, two-phase flow model was developed which included the effect of air and water flows in both the channel and GDL. The analysis from experimental measurements showed that the product of the friction factor and the gas flow Reynolds number was very nearly a constant, indicating that the model captures the critical physical features of the flow and is useful for the prediction of gas flow rate or pressure drop in a fuel cell microchannel.

  18. Dynamic modeling strategy for flow regime transition in gas-liquid two-phase flows

    International Nuclear Information System (INIS)

    In modeling gas-liquid two-phase flows, the concept of flow regime has been widely used to characterize the global interfacial structure of the flows. Nearly all constitutive relations that provide closures to the interfacial transfers in two-phase flow models, such as the two-fluid model, are often flow regime dependent. Currently, the determination of the flow regimes is primarily based on flow regime maps or transition criteria, which were developed for steady-state, fully-developed flows and have been widely applied in nuclear reactor system safety analysis codes. As two-phase flows are dynamic in nature (fully-developed two-phase flows generally do not exist in real applications), it is of importance to model the flow regime transition dynamically to be able to predict two-phase flows more accurately. The present work aims to develop a dynamic modeling strategy to determine flow regimes in gas-liquid two-phase flows through introduction of interfacial area transport equations (IATEs) within the framework of a two-fluid model. The IATE is a transport equation that models the interfacial area concentration by considering the creation and destruction of the interfacial area, such as the fluid particle (bubble or liquid droplet) disintegration, boiling and evaporation; and fluid particle coalescence and condensation, respectively. For the flow regimes beyond bubbly flows, a two-group IATE has been proposed, in which bubbles are divided into two groups based on their size and shapes, namely group-1 and group-2 bubbles. A preliminary approach to dynamically identify the flow regimes is discussed, in which discriminators are based on the predicted information, such as the void fraction and interfacial area concentration. The flow regime predicted with this method shows good agreement with the experimental observations. (author)

  19. The treatment of gaseous benzene by two-phase partitioning bioreactors: a high performance alternative to the use of biofilters

    Energy Technology Data Exchange (ETDEWEB)

    Davidson, C.T.; Daugulis, A.J. [Dept. of Chemical Engineering, Queen' s Univ., Kingston, ON (Canada)

    2003-07-01

    A 2-1 (1-1 working volume) two-phase partitioning bioreactor (TPPB) was used as an integrated scrubber/bioreactor in which the removal and destruction of benzene from a gas stream was achieved by the reactor's organic/aqueous liquid contents. The organic solvent used to trap benzene was n-hexadecane, and degradation of benzene was achieved in the aqueous phase using the bacterium Alcaligenes xylosoxidans Y234. A gas stream with a benzene concentration of 340 mg l{sup -1} at a flow rate of 0.414 l h{sup -1} was delivered to the system at a loading capacity of 140 g m{sup -3} h{sup -1}, and an elimination capacity of 133 g m{sup -3} h{sup -1} was achieved (the volume in this term is the total liquid volume of the TPPB). This elimination capacity is between 3 and 13 times greater than any benzene elimination achieved by biofiltration, a competing biological air treatment strategy. It was also determined that the evaluation of TPPB performance in terms of elimination capacity should include the cell mass present in the system, as this is a readily controllable quantity. A specific benzene utilization rate of 0.57 g benzene (g cells){sup -1} h{sup -1} was experimentally determined in a bioreactor with a cell concentration that varied dynamically between 0.2 and 1 g l{sup -1}. If it assumed that this specific benzene utilization rate (0.57 g g{sup -1} h{sup -1}) is independent of cell concentration, then a TPPB operated at high cell concentrations could potentially achieve elimination capacities several hundred times greater than those obtained with biofilters. (orig.)

  20. Two-phase treatment of inflamatory candidiasis of vulva

    Directory of Open Access Journals (Sweden)

    K. Drljević

    2006-02-01

    Full Text Available The purpose of this prospective study was to examine successfulnes of applaying two-phase treatment of vulvar inflamatory candidiasis. At the initial phase antimycotic izokonazol 1% nitrate in combination with corticosteriod diflucorton valerate (Travocort, Schering AG, Germany was localy applied, and then pure antimycotic izoconasol nitrate (Travogen, Schering AG, Germany. Parametars that have been analyzed in the first phase of treatment were regression of inflamatory changes of vulva, and in the second phase healing of fungal disease. Two-phase treatment of vulvar inflamatory candidiasis showed full therapy benefit at cured patients. The initial short-term local application of combination corticosteroid and antimycotic showed almost a hundred percent regression of inflamatory changes and simptoms of vulvar inflamatory candidiasis, without any side-effects noted.

  1. Weighted likelihood estimation under two-phase sampling

    CERN Document Server

    Saegusa, Takumi

    2011-01-01

    We develop asymptotic theory for weighted likelihood estimators (WLE) under two-phase stratified sampling without replacement. Although this sampling scheme induces dependence among observations, independent Bernoulli sampling is often assumed for convenience. Because our result shows that the asymptotic variance is smaller than under Bernoulli sampling, correctly accounting for a sampling scheme is particularly important. In this paper, we establish a Glivenko-Cantelli theorem, a theorem for rates of convergence of Z-estimators, and a Donsker theorem for the inverse probability weighted empirical processes under two-phase sampling. With these general results, we derive asymptotic distributions of the WLE of a finite dimensional parameter in a general semiparametric model where an estimator of a nuisance parameter is estimable either at regular or non-regular rates. We illustrate these results and methods in the Cox model with right censoring and interval censoring. Along the way we incorporate results for im...

  2. Mathematical modeling and the two-phase constitutive equations

    International Nuclear Information System (INIS)

    The problems raised by the mathematical modeling of two-phase flows are summarized. The models include several kinds of equations, which cannot be discussed independently, such as the balance equations and the constitutive equations. A review of the various two-phase one-dimensional models proposed to date, and of the constitutive equations they imply, is made. These models are either mixture models or two-fluid models. Due to their potentialities, the two-fluid models are discussed in more detail. To avoid contradictions, the form of the constitutive equations involved in two-fluid models must be sufficiently general. A special form of the two-fluid models, which has particular advantages, is proposed. It involves three mixture balance equations, three balance equations for slip and thermal non-equilibriums, and the necessary constitutive equations

  3. Recent advances in two-phase flow numerics

    Energy Technology Data Exchange (ETDEWEB)

    Mahaffy, J.H.; Macian, R. [Pennsylvania State Univ., University Park, PA (United States)

    1997-07-01

    The authors review three topics in the broad field of numerical methods that may be of interest to individuals modeling two-phase flow in nuclear power plants. The first topic is iterative solution of linear equations created during the solution of finite volume equations. The second is numerical tracking of macroscopic liquid interfaces. The final area surveyed is the use of higher spatial difference techniques.

  4. Recent advances in two-phase flow numerics

    International Nuclear Information System (INIS)

    The authors review three topics in the broad field of numerical methods that may be of interest to individuals modeling two-phase flow in nuclear power plants. The first topic is iterative solution of linear equations created during the solution of finite volume equations. The second is numerical tracking of macroscopic liquid interfaces. The final area surveyed is the use of higher spatial difference techniques

  5. Two-phase computer codes for zero-gravity applications

    Energy Technology Data Exchange (ETDEWEB)

    Krotiuk, W.J.

    1986-10-01

    This paper discusses the problems existing in the development of computer codes which can analyze the thermal-hydraulic behavior of two-phase fluids especially in low gravity nuclear reactors. The important phenomenon affecting fluid flow and heat transfer in reduced gravity is discussed. The applicability of using existing computer codes for space applications is assessed. Recommendations regarding the use of existing earth based fluid flow and heat transfer correlations are made and deficiencies in these correlations are identified.

  6. Simulation of two-phase flow with varying surface tension.

    OpenAIRE

    Lervåg, Karl Yngve

    2008-01-01

    This thesis is a study on the effects of varying surface tension along an interface separating two fluids. Varying surface tension leads to tangential forces along the interface. This is often called the Marangoni effect. These forces are discussed in detail, and two test cases are considered to analyse the Marangoni effect, and to verify the present implementation. The first test studies steady-state two-phase flow where the fluids are separated with plane interfaces and the flow is driv...

  7. Two-phase algorithms for the parametric shortest path problem

    OpenAIRE

    Fischer, Eldar; Lachish, Oded; Yuster, Raphael

    2010-01-01

    A {\\em parametric weighted graph} is a graph whose edges are labeled with continuous real functions of a single common variable. For any instantiation of the variable, one obtains a standard edge-weighted graph. Parametric weighted graph problems are generalizations of weighted graph problems, and arise in various natural scenarios. Parametric weighted graph algorithms consist of two phases. A {\\em preprocessing phase} whose input is a parametric weighted graph, and whose output is a data str...

  8. Two-Phase Slug Flow Experiments with Viscous Liquids

    OpenAIRE

    Diaz, Mariana J.C.

    2016-01-01

    The challenges behind the multiphase transport of oil and gas mixtures are increasing as the oil and gas industry is moving towards production from non-conventional reservoirs and in remote locations. Transport of high viscosity fluids in long multiphase pipelines is a particular challenge. Previous experiments have shown that gas-liquid slug flow is a frequent two-phase flow pattern at high liquid viscosities. The slug flow regime is an unstable flow, which may lead to operati...

  9. Two-fluid model for two-phase flow

    Science.gov (United States)

    Ishii, M.

    1987-06-01

    The two-fluid model formulation is discussed in detail. The emphasis of the paper is on the three-dimensional formulation and the closure issues. The origin of the interfacial and turbulent transfer terms in the averaged formulation is explained and their original mathematical forms are examined. The interfacial transfer of mass, momentum, and energy is proportional to the interfacial area and driving force. This is not a postulate but a result of the careful examination of the mathematical form of the exact interfacial terms. These two effects are considered separately. Since all the interfacial transfer terms involve the interfacial area concentration, the accurate modeling of the local interfacial area concentration is the first step to be taken for a development of a reliable two-fluid model closure relations. The interfacial momentum interaction has been studied in terms of the standard-drag, lift, virtual mass, and Basset forces. Available analytical and semi-empirical correlations and closure relations are reviewed and existing shortcomings are pointed out. The other major area of importance is the modeling of turbulent transfer in two-phase flow. The two-phase flow turbulence problem is coupled with the phase separation problem even in a steady-state fully developed flow. Thus the two-phase turbulence cannot be understood without understanding the interfacial drag and lift forces accurately. There are some indications that the mixing length type model may not be sufficient to describe the three-dimensional turbulent and flow structures. Although it is a very difficult challenge, the two-phase flow turbulence should be investigated both experimentally and analytically with long time-scale research.

  10. Two-phase Flow Distribution in Heat Exchanger Manifolds

    OpenAIRE

    Vist, Sivert

    2004-01-01

    The current study has investigated two-phase refrigerant flow distribution in heat exchange manifolds. Experimental data have been acquired in a heat exchanger test rig specially made for measurement of mass flow rate and gas and liquid distribution in the manifolds of compact heat exchangers. Twelve different manifold designs were used in the experiments, and CO2 and HFC-134a were used as refrigerants.

  11. A diffuse interface model for two-phase ferrofluid flows

    OpenAIRE

    Nochetto, Ricardo H.; Salgado, Abner J.; Tomas, Ignacio

    2016-01-01

    We develop a model describing the behavior of two-phase ferrofluid flows using phase field-techniques and present an energy-stable numerical scheme for it. For a simplified, yet physically realistic, version of this model and the corresponding numerical scheme we prove, in addition to stability, convergence and as by-product existence of solutions. With a series of numerical experiments we illustrate the potential of these simple models and their ability to capture basic phenomenological feat...

  12. Cyclic electrowinning/precipitation (CEP) system for the removal of heavy metal mixtures from aqueous solutions.

    Science.gov (United States)

    Grimshaw, Pengpeng; Calo, Joseph M; Hradil, George

    2011-11-15

    The description and operation of a novel cyclic electrowinning/precipitation (CEP) system for the simultaneous removal of mixtures of heavy metals from aqueous solutions are presented. CEP combines the advantages of electrowinning in a spouted particulate electrode (SPE) with that of chemical precipitation and redissolution, to remove heavy metals at low concentrations as solid metal deposits on particulate cathode particles without exporting toxic metal precipitate sludges from the process. The overall result is very large volume reduction of the heavy metal contaminants as a solid metal deposit on particles that can either be safely discarded as such, or further processed to recover particular metals. The performance of this system is demonstrated with data on the removal of mixtures of copper, nickel, and cadmium from aqueous solutions.

  13. Cyclic electrowinning/precipitation (CEP) system for the removal of heavy metal mixtures from aqueous solutions.

    Science.gov (United States)

    Grimshaw, Pengpeng; Calo, Joseph M; Hradil, George

    2011-11-15

    The description and operation of a novel cyclic electrowinning/precipitation (CEP) system for the simultaneous removal of mixtures of heavy metals from aqueous solutions are presented. CEP combines the advantages of electrowinning in a spouted particulate electrode (SPE) with that of chemical precipitation and redissolution, to remove heavy metals at low concentrations as solid metal deposits on particulate cathode particles without exporting toxic metal precipitate sludges from the process. The overall result is very large volume reduction of the heavy metal contaminants as a solid metal deposit on particles that can either be safely discarded as such, or further processed to recover particular metals. The performance of this system is demonstrated with data on the removal of mixtures of copper, nickel, and cadmium from aqueous solutions. PMID:22102792

  14. Two-phase mixtures explosion study: hydrogen and dusts

    International Nuclear Information System (INIS)

    The context of the study is the safety of the ITER installation. Indeed, studies have shown that it exists a risk for two-phase mixtures of hydrogen and dust can explode and create a safety risk for the ITER installation. This aims to obtain the fundamental data which characterize the explosion of these mixtures and to evaluate the pressure loads they can generate. To do so, experiments in spherical bomb have been carried out for hydrogen - oxygen - nitrogen mixtures at two initial temperatures (303 and 343 K) and pressures (50 and 100 kPa) for different hydrogen concentrations and different N2/O2 ratios. Explosion parameters like maximum combustion pressures (PMAX), deflagration indexes (KG or KST), combustion times (tC), fundamental flame speeds (SL0) and Markstein lengths have been determined. A kinetic modelling of the flame speed, using the COSILAB software was performed based on three detailed kinetic models available in the literature and allowed the calculation of the global activation energy on the basis of the kinetic model which showed the best agreement with the experimental data. Moreover equilibrium calculations were achieved to compare PMAX to the theoretical values. For two-phase mixtures, a new introduction device was tested and set up and experiments characterizing the explosions parameters of the two-phase mixtures have been performed in the spherical bomb. They were able to stress out the fact that, under some circumstances, dust explosion can be concomitant to a hydrogen explosion. (author)

  15. Flow pattern maps in two phase flow: present panorama

    International Nuclear Information System (INIS)

    In this work is presented a general panorama on the condition that watch over the related understanding to the pattern maps of flux regimes in the two-phase flow. The revision that has been done no exhaustive treat of flux patterns observed in vertical and horizontal ducts. As resulting of this investigation, it has been to make evident the necessity of lighting up with precision the use of flux pattern maps that they are not framed respect to really two-phase flow, but that they correspond really to the simultaneous flux of a gas and a liquid un miscible flowing in adiabatic conditions. The case more common of late these is the relative to the air-water mixture. The observed necessity has generated in the Thermo fluids Department of National Institute of Nuclear Research the restlessness of realizing experimental studies in this area. This in spite of being motive of research over 40 years and also of counting with a vast reported bibliography, on one the hand it has not conveyed to obtain representations of general character. And on the other hand it has origined a great confusion about the applicability of available information. In the same way it is described the advances developed in the experimental studies in the field of forced convection, as to only phase as one in two phases. (Author)

  16. Two-phase flow measurement by pulsed neutron activation techniques

    International Nuclear Information System (INIS)

    The Pulsed Neutron Activation (PNA) technique for measuring the mass flow velocity and the average density of two-phase mixtures is described. PNA equipment can be easily installed at different loops, and PNA techniques are non-intrusive and independent of flow regimes. These features of the PNA technique make it suitable for in-situ measurement of two-phase flows, and for calibration of more conventional two-phase flow measurement devices. Analytic relations governing the various PNA methods are derived. The equipment and procedures used in the first air-water flow measurement by PNA techniques are discussed, and recommendations are made for improvement of future tests. In the present test, the mass flow velocity was determined with an accuracy of 2%, and average densities were measured down to 0.08 g/cm3 with an accuracy of 0.04 g/cm3. Both the accuracy of the mass flow velocity measurement and the lower limit of the density measurement are functions of the injected activity and of the total number of counts. By using a stronger neutron source and a larger number of detectors, the measurable density can be decreased by a factor of 12 to .007 g/cm3 for 12.5 cm pipes, and to even lower ranges for larger pipes

  17. POTENSI MIKROEMULSI β-KAROTEN DALAM MENGHAMBAT FOTOOKSIDASI VITAMIN C SISTEM AQUEOUS [The Potential Inhibition of Β-Carotene Microemulsion on Vitamin C Photooxidation in Aqueous Systems

    Directory of Open Access Journals (Sweden)

    Setyaningrum Ariviani1*

    2011-06-01

    Full Text Available Photooxidation in food system causes nutritional losses and produces undesirable flavor, toxic and color compounds, which make foods unacceptable to consumers. The objective of this research was to determine β–carotene microemulsion inhibitory effect on vitamin C photooxidation in aqueous food model. Into aqueous food models containing vitamin C (450 ppm for model 1; 300 ppm for model 2 2% microemulsion or β–carotene microemulsion and erythrosine as photosensitizer, were added. The final β–carotene content in aqueous food model was equal to 0.6 or 12 ppm. The result indicated that microemulsion have ability to inhibit vitamin C photodegradation under light but did not show the ability under dark condition. The inhibitory effectiveness of both 6 and 12 ppm β-carotene microemulsion on vitamin C photodegradation were insignificant. The 6 ppm β-carotene microemulsion was proven to effectively inhibit vitamin C photooxidation in aqueous food model better than that of empty microemulsion or free β-carotene. The vitamin C photodegradation rate on model system 1 and 2 were 9.5 ± 2.48 and 6.4 ± 1.58 mg.L-1. hour-1 (β-carotene microemulsion; -14.8 ± 1.69 and -9.5 ± 1.23 mg.L-1. hour -1 (empty microemulsion; -16.0 ± 1.64 and -10.3 ± 0.46 mg.L-1. hour -1 (freeβ-carotene, respectively.

  18. Classification of natural circulation two-phase flow patterns using fuzzy inference on image analysis

    Energy Technology Data Exchange (ETDEWEB)

    Mesquita, R.N. de, E-mail: rnavarro@ipen.br [Nuclear Engineering Center, Instituto de Pesquisas Energeticas e Nucleares, IPEN/CNEN, Av. Professor Lineu Prestes, 2242 Cidade Universitaria, CEP 05508-000 Sao Paulo (Brazil); Masotti, P.H.F., E-mail: pmasotti@ipen.br [Nuclear Engineering Center, Instituto de Pesquisas Energeticas e Nucleares, IPEN/CNEN, Av. Professor Lineu Prestes, 2242 Cidade Universitaria, CEP 05508-000 Sao Paulo (Brazil); Penha, R.M.L., E-mail: rmpenha@ipen.br [Nuclear Engineering Center, Instituto de Pesquisas Energeticas e Nucleares, IPEN/CNEN, Av. Professor Lineu Prestes, 2242 Cidade Universitaria, CEP 05508-000 Sao Paulo (Brazil); Andrade, D.A., E-mail: delvonei@ipen.br [Nuclear Engineering Center, Instituto de Pesquisas Energeticas e Nucleares, IPEN/CNEN, Av. Professor Lineu Prestes, 2242 Cidade Universitaria, CEP 05508-000 Sao Paulo (Brazil); Sabundjian, G., E-mail: gdjian@ipen.br [Nuclear Engineering Center, Instituto de Pesquisas Energeticas e Nucleares, IPEN/CNEN, Av. Professor Lineu Prestes, 2242 Cidade Universitaria, CEP 05508-000 Sao Paulo (Brazil); Torres, W.M., E-mail: wmtorres@ipen.br [Nuclear Engineering Center, Instituto de Pesquisas Energeticas e Nucleares, IPEN/CNEN, Av. Professor Lineu Prestes, 2242 Cidade Universitaria, CEP 05508-000 Sao Paulo (Brazil); and others

    2012-09-15

    Highlights: Black-Right-Pointing-Pointer A fuzzy classification system for two-phase flow instability patterns is developed. Black-Right-Pointing-Pointer Flow patterns are classified based on images of natural circulation experiments. Black-Right-Pointing-Pointer Fuzzy inference is optimized to use single grayscale profiles as input. - Abstract: Two-phase flow on natural circulation phenomenon has been an important theme on recent studies related to nuclear reactor designs. The accuracy of heat transfer estimation has been improved with new models that require precise prediction of pattern transitions of flow. In this work, visualization of natural circulation cycles is used to study two-phase flow patterns associated with phase transients and static instabilities of flow. A Fuzzy Flow-type Classification System (FFCS) was developed to classify these patterns based only on image extracted features. Image acquisition and temperature measurements were simultaneously done. Experiments in natural circulation facility were adjusted to generate a series of characteristic two-phase flow instability periodic cycles. The facility is composed of a loop of glass tubes, a heat source using electrical heaters, a cold source using a helicoidal heat exchanger, a visualization section and thermocouples positioned over different loop sections. The instability cyclic period is estimated based on temperature measurements associated with the detection of a flow transition image pattern. FFCS shows good results provided that adequate image acquisition parameters and pre-processing adjustments are used.

  19. Dehalogenation of Aryl Halides Catalyzed by Montmorillonite Immobilized Bimetal Catalyst in Aqueous System

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A novel bisupported bimetal catalyst PVP-PdCl2-FeSO4/Al-Mont-PEG600 was prepared by immobilization of PVP (poly (N-vinyl-2-pyrrolidone)) supported bimetallic catalyst using alumina pillared inartificial montmorillonite as the carrier. This catalyst has good dehalogenation activity and selectivity to aryl halides-o-chlorotoluene in aqueous system in the presence of phase transfer catalyst (PEG) and sodium formate as hydrogen source. The catalyst also shows good reusability.

  20. Ruthenium on rutile catalyst, catalytic system, and method for aqueous phase hydrogenations

    Science.gov (United States)

    Elliot, Douglas C.; Werpy, Todd A.; Wang, Yong; Frye, Jr., John G.

    2001-01-01

    An essentially nickel- and rhenium-free catalyst is described comprising ruthenium on a titania support where the titania is greater than 75% rutile. A catalytic system containing a nickel-free catalyst comprising ruthenium on a titania support where the titania is greater than 75% rutile, and a method using this catalyst in the hydrogenation of an organic compound in the aqueous phase is also described.