Creating Drug Solubilization Compartments via Phase Separation in Multicomponent Buccal Patches Prepared by Direct Hot Melt Extrusion-Injection Molding.

Science.gov (United States)

Alhijjaj, Muqdad; Bouman, Jacob; Wellner, Nikolaus; Belton, Peter; Qi, Sheng

2015-12-07

Creating in situ phase separation in solid dispersion based formulations to allow enhanced functionality of the dosage form, such as improving dissolution of poorly soluble model drug as well as being mucoadhesive, can significantly maximize the in vitro and in vivo performance of the dosage form. This formulation strategy can benefit a wide range of solid dosage forms for oral and alternative routes of delivery. This study using buccal patches as an example created separated phases in situ of the buccal patches by selecting the excipients with different miscibility with each other and the model drug. The quaternary dispersion based buccal patches containing PEG, PEO, Tween 80, and felodipine were prepared by direct hot melt extrusion-injection molding (HME-IM). The partial miscibility between Tween 80 and semicrystalline PEG-PEO led to the phase separation after extrusion. The Tween phases acted as drug solubilization compartments, and the PEG-PEO phase had the primary function of providing mucoadhesion and carrier controlled dissolution. As felodipine was preferably solubilized in the amorphous regions of PEG-PEO, the high crystallinity of PEG-PEO resulted in an overall low drug solubilizing capacity. Tween 80 was added to improve the solubilization capacity of the system as the model drug showed good solubility in Tween. Increasing the drug loading led to the supersaturation of drug in Tween compartments and crystalline drug dispersed in PEG-PEO phases. The spatial distribution of these phase-separated compartments was mapped using X-ray micro-CT, which revealed that the domain size and heterogeneity of the phase separation increased with increasing the drug loading. The outcome of this study provides new insights into the applicability of in situ formed phase separation as a formulation strategy for the delivery of poorly soluble drugs and demonstrated the basic principle of excipient selection for such technology.

Solubility data for cement hydrate phases (25oC)

International Nuclear Information System (INIS)

Atkins, M.; Glasser, F.P.; Kindness, A.; Macphee, D.E.

1991-05-01

Solubility measurements were performed on most of the more thermodynamically-stable cement hydrate phases, at 25 o C. The results for each hydrate phase are summarised in the form of datasheets. Solubility properties are discussed, and where possible a K sp value is calculated. The data are compared with the data in the literature. (author)

From Single Microparticles to Microfluidic Emulsification: Fundamental Properties (Solubility, Density, Phase Separation from Micropipette Manipulation of Solvent, Drug and Polymer Microspheres

Directory of Open Access Journals (Sweden)

Koji Kinoshita

2016-11-01

Full Text Available The micropipette manipulation technique is capable of making fundamental single particle measurements and analyses. This information is critical for establishing processing parameters in systems such as microfluidics and homogenization. To demonstrate what can be achieved at the single particle level, the micropipette technique was used to form and characterize the encapsulation of Ibuprofen (Ibp into poly(lactic-co-glycolic acid (PLGA microspheres from dichloromethane (DCM solutions, measuring the loading capacity and solubility limits of Ibp in typical PLGA microspheres. Formed in phosphate buffered saline (PBS, pH 7.4, Ibp/PLGA/DCM microdroplets were uniformly solidified into Ibp/PLGA microparticles up to drug loadings (DL of 41%. However, at DL 50 wt% and above, microparticles showed a phase separated pattern. Working with single microparticles, we also estimated the dissolution time of pure Ibp microspheres in the buffer or in detergent micelle solutions, as a function of the microsphere size and compare that to calculated dissolution times using the Epstein-Plesset (EP model. Single, pure Ibp microparticles precipitated as liquid phase microdroplets that then gradually dissolved into the surrounding PBS medium. Analyzing the dissolution profiles of Ibp over time, a diffusion coefficient of 5.5 ± 0.2 × 10−6 cm2/s was obtained by using the EP model, which was in excellent agreement with the literature. Finally, solubilization of Ibp into sodium dodecyl sulfate (SDS micelles was directly visualized microscopically for the first time by the micropipette technique, showing that such micellization could increase the solubility of Ibp from 4 to 80 mM at 100 mM SDS. We also introduce a particular microfluidic device that has recently been used to make PLGA microspheres, showing the importance of optimizing the flow parameters. Using this device, perfectly smooth and size-homogeneous microparticles were formed for flow rates of 0.167 mL/h for

Microcellular foams via phase separation

International Nuclear Information System (INIS)

Young, A.T.

1985-01-01

A study of wide variety of processes for making plastic foams shows that phase separation processes for polymers from solutions offers the most viable methods for obtaining rigid plastic foams which met the physical requirements for fusion target designs. Four general phase separation methods have been shown to give polymer foams with densities less than 0.1 g/cm 3 and cell sizes of 30μm or less. These methods involve the utilization of non-solvent, chemical or thermal cooling processes to achieve a controlled phase separation wherein either two distinct phases are obtained where the polymer phase is a continuous phase or two bicontinuous phases are obtained where both the polymer and solvent are interpenetrating, continuous, labyrinthine phases. Subsequent removal of the solvent gives the final foam structure

Polymer solution phase separation: Microgravity simulation

Science.gov (United States)

Cerny, Lawrence C.; Sutter, James K.

1989-01-01

In many multicomponent systems, a transition from a single phase of uniform composition to a multiphase state with separated regions of different composition can be induced by changes in temperature and shear. The density difference between the phase and thermal and/or shear gradients within the system results in buoyancy driven convection. These differences affect kinetics of the phase separation if the system has a sufficiently low viscosity. This investigation presents more preliminary developments of a theoretical model in order to describe effects of the buoyancy driven convection in phase separation kinetics. Polymer solutions were employed as model systems because of the ease with which density differences can be systematically varied and because of the importance of phase separation in the processing and properties of polymeric materials. The results indicate that the kinetics of the phase separation can be performed viscometrically using laser light scattering as a principle means of following the process quantitatively. Isopycnic polymer solutions were used to determine the viscosity and density difference limits for polymer phase separation.

Phase separation and shape deformation of two-phase membranes

International Nuclear Information System (INIS)

Jiang, Y.; Lookman, T.; Saxena, A.

2000-01-01

Within a coupled-field Ginzburg-Landau model we study analytically phase separation and accompanying shape deformation on a two-phase elastic membrane in simple geometries such as cylinders, spheres, and tori. Using an exact periodic domain wall solution we solve for the shape and phase separating field, and estimate the degree of deformation of the membrane. The results are pertinent to preferential phase separation in regions of differing curvature on a variety of vesicles. (c) 2000 The American Physical Society

Liquid-phase separation with the rotational particle separator

NARCIS (Netherlands)

Kemenade, van H.P.; Mondt, E.; Hendriks, A.J.A.M.; Verbeek, P.H.J.

2003-01-01

Recently, the rotational particle separator (RPS) was introduced as a new technique for separating solid and/or liquid particles of 0.1 m and larger from gases. In this patented technique the principles of centrifugation are exploited to enhance separation of small-sized phases and particulate

Supercritical fluid chromatographic resolution of water soluble isomeric carboxyl/amine terminated peptides facilitated via mobile phase water and ion pair formation.

Science.gov (United States)

Patel, M A; Riley, F; Ashraf-Khorassani, M; Taylor, L T

2012-04-13

Both analytical scale and preparative scale packed column supercritical fluid chromatography (SFC) have found widespread applicability for chiral separations of multiple polar pharmaceutical candidates. However, SFC is rapidly becoming an achiral technique. More specifically, ion pair SFC is finding greater utility for separation of ionic analytes such as amine salts and organic sulfonates. The key to this success is, in part, the incorporation of additives such as trifluoroacetic acid and ammonium acetate into the mobile phase in association with a wide variety of both bonded silica stationary phases and high purity bare silica. Ion pairing SFC coupled with evaporative light scattering detection and mass spectrometric detection is presented here for the separation of water soluble, uncapped, isomeric peptide pairs that differ in amino acid arrangement. The separation is best achieved on either diol-bonded silica or bare silica with 1-5% (w/w) water as a significant ingredient in the mobile phase. Nitrogenous stationary phases such as 2-ethylpyridine, which had been very successful for the separation of capped peptides failed to yield the desired separation regardless of the mobile phase composition. A HILIC type retention mechanism is postulated for the separation of both isomeric uncapped peptide pairs. Copyright © 2012 Elsevier B.V. All rights reserved.

Methods for calculation of engineering parameters for gas separation. [vapor pressure and solubility of gases in organic liquids

Science.gov (United States)

Lawson, D. D.

1979-01-01

A group additivity method is generated which allows estimation, from the structural formulas alone, of the energy of vaporization and the molar volume at 25 C of many nonpolar organic liquids. Using these two parameters and appropriate thermodynamic relations, the vapor pressure of the liquid phase and the solubility of various gases in nonpolar organic liquids are predicted. It is also possible to use the data to evaluate organic and some inorganic liquids for use in gas separation stages or liquids as heat exchange fluids in prospective thermochemical cycles for hydrogen production.

[Fast separation and analysis of water-soluble vitamins in spinach by capillary electrophoresis with high voltage].

Science.gov (United States)

Hu, Xiaoqin; You, Huiyan

2009-11-01

In capillary electrophoresis, 0-40 kV (even higher) voltage can be reached by a connecting double-model high voltage power supply. In the article, water-soluble vitamins, VB1, VB2, VB6, VC, calcium D-pantothenate, D-biotin, nicotinic acid and folic acid in vegetable, were separated by using the high voltage power supply under the condition of electrolyte water solution as running buffer. The separation conditions, such as voltage, the concentration of buffer and pH value etc. , were optimized during the experiments. The results showed that eight water-soluble vitamins could be baseline separated in 2.2 min at 40 kV applied voltage, 25 mmol/L sodium tetraborate buffer solution (pH 8.8). The water-soluble vitamins in spinach were quantified and the results were satisfied. The linear correlation coefficients of the water-soluble vitamins ranged from 0.9981 to 0.9999. The detection limits ranged from 0.2 to 0.3 mg/L. The average recoveries ranged from 88.0% to 100.6% with the relative standard deviations (RSD) range of 1.15%-4.13% for the spinach samples.

Creating Drug Solubilization Compartments via Phase Separation in Multicomponent Buccal Patches Prepared by Direct Hot Melt Extrusion-Injection Molding

NARCIS (Netherlands)

Alhijjaj, Muqdad; Bouman, Jacob; Wellner, Nikolaus; Belton, Peter; Qi, Sheng

2015-01-01

Creating in situ phase separation in solid dispersion based formulations to allow enhanced functionality of the dosage form, such as improving dissolution of poorly soluble model drug as well as being mucoadhesive, can significantly maximize the in vitro and in vivo performance of the dosage

Limited solubility of iron in the Sun's interior

International Nuclear Information System (INIS)

Pollock, E.L.; Alder, B.J.

1978-01-01

Stripped iron nuclei in a hydrogen plasma under central solar conditions, according to the classical Debye-Huckel model, would undergo phase separation for concentrations well below the cosmic abundance value. The higher concentration corrections, needed to characterise the iron-rich phase, lead to enhanced solubility for a simplified model where the electrons form a uniform background. Support for an iron-rich phase coalescing in the solar interior requires more accurate treatment of bound and partially bound electrons in such a mixture. The results of the Debye-Huckel model where the electrons are treated discretely and as a continuum, are reported here and support the possibility of phase separation. The physical cause of that phase separation is simply that the potential energy is lower in the separated phase than in the mixture because the local charge neutralisation is much better satisfied in the two separated phases. (author)

Rapid analysis of water- and fat-soluble vitamins by electrokinetic chromatography with polymeric micelle as pseudostationary phase.

Science.gov (United States)

Ni, Xinjiong; Xing, Xiaoping; Cao, Yuhua; Cao, Guangqun

2014-11-28

A novel polymeric micelle, formed by random copolymer poly (stearyl methacrylate-co-methacrylic acid) (P(SMA-co-MAA)) has been used as pseudostationary phase (PSP) in electrokinetic chromatography (EKC) for simultaneous and rapid determination of 11 kinds of water- and fat-soluble vitamins in this work. The running buffer consisting of 1% (w/v) P(SMA-co-MAA), 10% (v/v) 1-butanol, 20% (v/v) acetonitrile, and 30 mM Palitzsch buffer solution (pH 9.2) was applied to improve the selectivity and efficiency, as well as to shorten analysis time. 1-Butanol and acetonitrile as the organic solvent modifiers played the most important roles for rapid separation of these vitamins. The effects of organic solvents on microstructure of the polymeric micelle were investigated. The organic solvents swell the polymeric micelle by three folds, lower down the surface charge density and enhance the microenviromental polarity of the polymeric micelle. The 11 kinds of water- and fat-soluble vitamins could be baseline separated within 13 min. The method was applied to determine water- and fat-soluble vitamins in commercial vitamin sample; the recoveries were between 93% and 111% with the relative standard derivations (RSDs) less than 5%. The determination results matched the label claim. Copyright © 2014 Elsevier B.V. All rights reserved.

Comparison of GC stationary phases for the separation of fatty acid methyl esters in biodiesel fuels.

Science.gov (United States)

Goding, Julian C; Ragon, Dorisanne Y; O'Connor, Jack B; Boehm, Sarah J; Hupp, Amber M

2013-07-01

The fatty acid methyl ester (FAME) content of biodiesel fuels has traditionally been determined using gas chromatography with a polar stationary phase. In this study, a direct comparison of the separation of FAMEs present in various biodiesel samples on three polar stationary phases and one moderately polar stationary phase (with comparable column dimensions) was performed. Retention on each column was based on solubility in and polarity of the phase. Quantitative metrics describing the resolution of important FAME pairs indicate high resolution on all polar columns, yet the best resolution, particularly of geometric isomers, is achieved on the cyanopropyl column. In addition, the separation of four C18 monounsaturated isomers was optimized and the elution order determined on each column. FAME composition of various biodiesel fuel types was determined on each column to illustrate (1) chemical differences in biodiesels produced from different feedstocks and (2) chemical similarities in biodiesels of the same feedstock type produced in different locations and harvest seasons.

Phase separator safety valve blow-off.

CERN Multimedia

G. Perinic

2006-01-01

The fast discharge of the CMS solenoid leads to a pressure rise in the phase separator. On August 28th, a fast discharge was triggered at a current level of 19.1 kA. The pressure in the phase separator increased up to the set pressure of the safety valve and some helium was discharged. In consequence of this and prevoious similar observations the liquid helium level in the phase separator has been reduced from 60% to 50% and later to 45% in order to reduce the helium inventory in the magnet.

Thermodynamics of phase-separating nanoalloys: Single particles and particle assemblies

Science.gov (United States)

Fèvre, Mathieu; Le Bouar, Yann; Finel, Alphonse

2018-05-01

The aim of this paper is to investigate the consequences of finite-size effects on the thermodynamics of nanoparticle assemblies and isolated particles. We consider a binary phase-separating alloy with a negligible atomic size mismatch, and equilibrium states are computed using off-lattice Monte Carlo simulations in several thermodynamic ensembles. First, a semi-grand-canonical ensemble is used to describe infinite assemblies of particles with the same size. When decreasing the particle size, we obtain a significant decrease of the solid/liquid transition temperatures as well as a growing asymmetry of the solid-state miscibility gap related to surface segregation effects. Second, a canonical ensemble is used to analyze the thermodynamic equilibrium of finite monodisperse particle assemblies. Using a general thermodynamic formulation, we show that a particle assembly may split into two subassemblies of identical particles. Moreover, if the overall average canonical concentration belongs to a discrete spectrum, the subassembly concentrations are equal to the semi-grand-canonical equilibrium ones. We also show that the equilibrium of a particle assembly with a prescribed size distribution combines a size effect and the fact that a given particle size assembly can adopt two configurations. Finally, we have considered the thermodynamics of an isolated particle to analyze whether a phase separation can be defined within a particle. When studying rather large nanoparticles, we found that the region in which a two-phase domain can be identified inside a particle is well below the bulk phase diagram, but the concentration of the homogeneous core remains very close to the bulk solubility limit.

diffusive phase separation

Directory of Open Access Journals (Sweden)

Nobuyuki Kenmochi

1996-01-01

w is constrained to have double obstacles σ*≤w≤σ* (i.e., σ* and σ* are the threshold values of w. The objective of this paper is to discuss the semigroup {S(t} associated with the phase separation model, and construct its global attractor.

Phase separation of self-propelled ballistic particles

Science.gov (United States)

Bruss, Isaac R.; Glotzer, Sharon C.

2018-04-01

Self-propelled particles phase-separate into coexisting dense and dilute regions above a critical density. The statistical nature of their stochastic motion lends itself to various theories that predict the onset of phase separation. However, these theories are ill-equipped to describe such behavior when noise becomes negligible. To overcome this limitation, we present a predictive model that relies on two density-dependent timescales: τF, the mean time particles spend between collisions; and τC, the mean lifetime of a collision. We show that only when τF<τC do collisions last long enough to develop a growing cluster and initiate phase separation. Using both analytical calculations and active particle simulations, we measure these timescales and determine the critical density for phase separation in both two and three dimensions.

Separation of Corn Fiber and Conversion to Fuels and Chemicals Phase II: Pilot-scale Operation

Energy Technology Data Exchange (ETDEWEB)

Abbas, Charles; Beery, Kyle; Orth, Rick; Zacher, Alan

2007-09-28

The purpose of the Department of Energy (DOE)-supported corn fiber conversion project, “Separation of Corn Fiber and Conversion to Fuels and Chemicals Phase II: Pilot-scale Operation” is to develop and demonstrate an integrated, economical process for the separation of corn fiber into its principal components to produce higher value-added fuel (ethanol and biodiesel), nutraceuticals (phytosterols), chemicals (polyols), and animal feed (corn fiber molasses). This project has successfully demonstrated the corn fiber conversion process on the pilot scale, and ensured that the process will integrate well into existing ADM corn wet-mills. This process involves hydrolyzing the corn fiber to solubilize 50% of the corn fiber as oligosaccharides and soluble protein. The solubilized fiber is removed and the remaining fiber residue is solvent extracted to remove the corn fiber oil, which contains valuable phytosterols. The extracted oil is refined to separate the phytosterols and the remaining oil is converted to biodiesel. The de-oiled fiber is enzymatically hydrolyzed and remixed with the soluble oligosaccharides in a fermentation vessel where it is fermented by a recombinant yeast, which is capable of fermenting the glucose and xylose to produce ethanol. The fermentation broth is distilled to remove the ethanol. The stillage is centrifuged to separate the yeast cell mass from the soluble components. The yeast cell mass is sold as a high-protein yeast cream and the remaining sugars in the stillage can be purified to produce a feedstock for catalytic conversion of the sugars to polyols (mainly ethylene glycol and propylene glycol) if desirable. The remaining materials from the purification step and any materials remaining after catalytic conversion are concentrated and sold as a corn fiber molasses. Additional high-value products are being investigated for the use of the corn fiber as a dietary fiber sources.

Model evaluation for the prediction of solubility of active pharmaceutical ingredients (APIs to guide solid–liquid separator design

Directory of Open Access Journals (Sweden)

Kuveneshan Moodley

2018-05-01

Full Text Available The assumptions and models for solubility modelling or prediction in systems using non-polar solvents, or water and complex triterpene and other active pharmaceutical ingredients as solutes aren't well studied. Furthermore, the assumptions concerning heat capacity effects (negligibility, experimental values or approximations are explored, using non-polar solvents (benzene, or water as reference solvents, for systems with solute melting points in the range of 306–528 K and molecular weights in the range of 90–442 g/mol. New empirical estimation methods for the ΔfusCpi of APIs are presented which correlate the solute molecular masses and van der Waals surface areas with ΔfusCpi. Separate empirical parameters were required for oxygenated and non-oxygenated solutes. Subsequently, the predictive capabilities of the various approaches to solubility modelling for complex pharmaceuticals, for which data is limited, are analysed. The solute selection is based on a principal component analysis, considering molecular weights, fusion temperatures, and solubilities in a non-polar solvent, alcohol, and water, where data was available. New NRTL-SAC parameters were determined for selected steroids, by regression. The original UNIFAC, modified UNIFAC (Dortmund, COSMO-RS (OL, and COSMO-SAC activity coefficient predictions are then conducted, based on the availability of group constants and sigma profiles. These are undertaken to assess the predictive capabilities of these models when each assumption concerning heat capacity is employed. The predictive qualities of the models are assessed, based on the mean square deviation and provide guidelines for model selection, and assumptions concerning phase equilibrium, when designing solid–liquid separators for the pharmaceutical industry on process simulation software. The most suitable assumption regarding ΔfusCpi was found to be system specific, with modified UNIFAC (Dortmund performing well in benzene as

Electronic phase separation and high temperature superconductors

International Nuclear Information System (INIS)

Kivelson, S.A.

1994-01-01

The authors review the extensive evidence from model calculations that neutral holes in an antiferromagnet separate into hole-rich and hole-poor phases. All known solvable limits of models of holes in a Heisenberg antiferromagnet exhibit this behavior. The authors show that when the phase separation is frustrated by the introduction of long-range Coulomb interactions, the typical consequence is either a modulated (charge density wave) state or a superconducting phase. The authors then review some of the strong experimental evidence supporting an electronically-driven phase separation of the holes in the cuprate superconductors and the related Ni oxides. Finally, the authors argue that frustrated phase separation in these materials can account for many of the anomalous normal state properties of the high temperature superconductors and provide the mechanism of superconductivity. In particular, it is shown that the T-linear resistivity of the normal state is a paraconductivity associated with a novel composite pairing, although the ordered superconducting state is more conventional

Structural Changes of PVDF Membranes by Phase Separation Control

International Nuclear Information System (INIS)

Lee, Semin; Kim, Sung Soo

2016-01-01

Thermally induced phase separation (TIPS) and nonsolvent induced phase separation (NIPS) were simultaneously induced for the preparation of flat PVDF membranes. N-methyl-2-pyrrolidone (NMP) was used as a solvent and dibutyl-phthlate (DBP) was used as a diluent for PVDF. When PVDF was melt blended with NMP and DBP, crystallization temperature was lowered for TIPS and unstable region was expanded for NIPS. Ratio of solvent to diluent changed the phase separation mechanism to obtain the various membrane structures. Contact mode of dope solution with nonsolvent determined the dominant phase separation behavior. Since heat transfer rate was greater than mass transfer rate, surface structure was formed by NIPS and inner structure was by TIPS. Quenching temperature of dope solution also affected the phase separation mechanism and phase separation rate to result in the variation of structure

Use of two-phase aqueous systems based on water-soluble polymers in thin-layer and extraction chromatography for recovery and separtion of actinides

International Nuclear Information System (INIS)

Molochnikova, N.P.; Shkinev, V.M.; Myasoedov, B.F.

1995-01-01

The feasibility has been demonstrated of using two-phase aqueous systems based on water-soluble polymers, polyethylene glycol and dextran sulfate, in thin-layer and extraction chromatography for recovery and separation of actinides. A convenient method has been proposed for continuous recovery of 239 Np from 243 Am, originating from differences in sorption of tri- and pentavalent actinides from sulfate solutions containing potassium phosphotungstate by silica gel impregnated with polyethylene glycol. New plates for thin-layer chromatography using water-soluble polymers have been developed. These plates were used to study behavior of americium in various oxidation states in thin sorbent layers

Phase separation in an ionomer glass

DEFF Research Database (Denmark)

Pedersen, Malene Thostrup; Tian, K.V.; Dobó-Nagy, C.

2015-01-01

The G338 ionomer glass is a fluoro-alumino-silicate system, which is used as the powder component of glass ionomer cements (GICs) in dental applications. However, despite progress in understanding the nature of this glass, chemical identity of its separated amorphous phases has not yet been...... amorphous phases in G388 are Ca/Na-Al-Si-O, Ca-Al-F and Ca-P-O-F phases, respectively. However, the exact chemical compositions of the three phases still require further exploration. The results of this work are important for understanding the impact of phase separation within ionomer glasses on the setting...... conclusively determined. In this work, we identify these phases by performing differential scanning calorimetry (DSC) and X-ray diffraction (XRD) analyses on both the as-received glass and heat-treated samples. We detected three glass transitions in the as-received G338 glass during DSC upscaning, implying...

Effect of geometric parameters of liquid-gas separator units on phase separation performance

Energy Technology Data Exchange (ETDEWEB)

Mo, Songping; Chen, Xueqing; Chen, Ying [Guangdong University of Technology, Seoul (China); Yang, Zhen [Tsinghua University, Beijing (China)

2015-07-15

Five liquid-gas separator units were designed and constructed based on a new concept of a validated high-performance condenser. Each separator unit consists of two united T-junctions and an apertured baffle. The separator units have different header diameters or different baffles with different diameters of the liquid-gas separation hole. The phase separation characteristics of the units were investigated at inlet air superficial velocities from 1.0m/s to 33.0m/s and water superficial velocities from 0.0015 m/s to 0..50 m/s. The experimental results showed that the liquid height, liquid flow rate through the separation hole, and liquid separation efficiency increased with increased header diameter and decreased diameter of the separation hole. The geometric structures of the separator units affected the phase separation characteristics by influencing the liquid height in the header and the liquid flow rate through the separation hole.

Phase separation and large deviations of lattice active matter

Science.gov (United States)

Whitelam, Stephen; Klymko, Katherine; Mandal, Dibyendu

2018-04-01

Off-lattice active Brownian particles form clusters and undergo phase separation even in the absence of attractions or velocity-alignment mechanisms. Arguments that explain this phenomenon appeal only to the ability of particles to move persistently in a direction that fluctuates, but existing lattice models of hard particles that account for this behavior do not exhibit phase separation. Here we present a lattice model of active matter that exhibits motility-induced phase separation in the absence of velocity alignment. Using direct and rare-event sampling of dynamical trajectories, we show that clustering and phase separation are accompanied by pronounced fluctuations of static and dynamic order parameters. This model provides a complement to off-lattice models for the study of motility-induced phase separation.

A novel mechanical model for phase-separation in debris flows

Science.gov (United States)

Pudasaini, Shiva P.

2015-04-01

Understanding the physics of phase-separation between solid and fluid phases as a two-phase mass moves down slope is a long-standing challenge. Here, I propose a fundamentally new mechanism, called 'separation-flux', that leads to strong phase-separation in avalanche and debris flows. This new model extends the general two-phase debris flow model (Pudasaini, 2012) to include a separation-flux mechanism. The new flux separation mechanism is capable of describing and controlling the dynamically evolving phase-separation, segregation, and/or levee formation in a real two-phase, geometrically three-dimensional debris flow motion and deposition. These are often observed phenomena in natural debris flows and industrial processes that involve the transportation of particulate solid-fluid mixture material. The novel separation-flux model includes several dominant physical and mechanical aspects that result in strong phase-separation (segregation). These include pressure gradients, volume fractions of solid and fluid phases and their gradients, shear-rates, flow depth, material friction, viscosity, material densities, boundary structures, gravity and topographic constraints, grain shape, size, etc. Due to the inherent separation mechanism, as the mass moves down slope, more and more solid particles are brought to the front, resulting in a solid-rich and mechanically strong frontal surge head followed by a weak tail largely consisting of the viscous fluid. The primary frontal surge head followed by secondary surge is the consequence of the phase-separation. Such typical and dominant phase-separation phenomena are revealed here for the first time in real two-phase debris flow modeling and simulations. However, these phenomena may depend on the bulk material composition and the applied forces. Reference: Pudasaini, Shiva P. (2012): A general two-phase debris flow model. J. Geophys. Res., 117, F03010, doi: 10.1029/2011JF002186.

Solubility and phase behaviors of DGA compounds in supercritical CO2

International Nuclear Information System (INIS)

Li Jia; Meng Qingyang

2010-01-01

Solubility and phase behaviors of DGA compounds in supercritical CO 2 (Sc-CO 2 ) was investigated. The results indicated: The dissolving ability of these six DGA compounds in Sc-CO 2 is TEDGA> TBDGA>THDGA>TODGA>TDDGA >TDdDGA; The solubility of DGA in Sc-CO 2 increase with increasing density of CO 2 , pressure and δ CO 2 ; The structure of DGA compounds is the mainly factor effected on solubility of DGA compounds in Sc-CO 2 , and the effect of hydrophobicity on solubility is much smaller than that of DGA's structure. In Sc-CO 2 , TDDGA and TDdDGA can't form the available extraction system; TEDGA and TBDGA are useful for extraction of solid powder; TODGA and THDGA are both useful for extraction of solid powder and solution contained some kind of actinide metal. (authors)

Comparing monolithic and fused core HPLC columns for fast chromatographic analysis of fat-soluble vitamins.

Science.gov (United States)

Kurdi, Said El; Muaileq, Dina Abu; Alhazmi, Hassan A; Bratty, Mohammed Al; Deeb, Sami El

2017-06-27

HPLC stationary phases of monolithic and fused core type can be used to achieve fast chromatographic separation as an alternative to UPLC. In this study, monolithic and fused core stationary phases are compared for fast separation of four fat-soluble vitamins. Three new methods on the first and second generation monolithic silica RP-18e columns and a fused core pentafluoro-phenyl propyl column were developed. Application of three fused core columns offered comparable separations of retinyl palmitate, DL-α-tocopheryl acetate, cholecalciferol and menadione in terms of elution speed and separation efficiency. Separation was achieved in approx. 5 min with good resolution (Rs > 5) and precision (RSD ≤ 0.6 %). Monolithic columns showed, however, a higher number of theoretical plates, better precision and lower column backpressure than the fused core column. The three developed methods were successfully applied to separate and quantitate fat-soluble vitamins in commercial products.

Phase separation and pressure drop of two-phase flow in vertical manifolds

International Nuclear Information System (INIS)

Zetzmann, K.

1982-01-01

The splitting of a two-phase mass flow in a tube manifold results in a separation between liquid and gas phase. A study is presented of the phase distribution and the related two-phase pressure drop for vertical manifolds in the technically relevant geometry and flow parameter region of an air-water-flow. At the outlet changes in the gas/fluid-radio are observed which are proportional to this ratio at the inlet. The separation characteristic strongly depends on the massflow through the junction. Empirical equations are given to calculate the separation. Measuring the pressure drop at main- and secondary tube of the manifold the additional pressure drop can be obtained. If these results are related with the dynamic pressure at the inlet, two-phase resistance coefficients can be deduced, which may be tested by empirical relations. (orig.) [de

Phase separation of superconducting phases in the Penson–Kolb–Hubbard model

International Nuclear Information System (INIS)

Kapcia, Konrad Jerzy; Czart, Wojciech Robert; Ptok, Andrzej

2016-01-01

In this paper, we determine the phase diagrams (for T = 0 as well as T > 0) of the Penson–Kolb–Hubbard model for two dimensional square lattice within Hartree–Fock mean-field theory focusing on an investigation of superconducting phases and on a possibility of the occurrence of the phase separation. We obtain that the phase separation, which is a state of coexistence of two different superconducting phases (with s- and η-wave symmetries), occurs in definite ranges of the electron concentration. In addition, increasing temperature can change the symmetry of the superconducting order parameter (from η-wave into s-wave). The system considered exhibits also an interesting multicritical behaviour including bicritical points. The relevance of the results to experiments for real materials is also discussed. (author)

Phase Separation of Superconducting Phases in the Penson-Kolb-Hubbard Model

Science.gov (United States)

Jerzy Kapcia, Konrad; Czart, Wojciech Robert; Ptok, Andrzej

2016-04-01

In this paper, we determine the phase diagrams (for T = 0 as well as T > 0) of the Penson-Kolb-Hubbard model for two dimensional square lattice within Hartree-Fock mean-field theory focusing on an investigation of superconducting phases and on a possibility of the occurrence of the phase separation. We obtain that the phase separation, which is a state of coexistence of two different superconducting phases (with s- and η-wave symmetries), occurs in definite ranges of the electron concentration. In addition, increasing temperature can change the symmetry of the superconducting order parameter (from η-wave into s-wave). The system considered exhibits also an interesting multicritical behaviour including bicritical points. The relevance of the results to experiments for real materials is also discussed.

Comparing monolithic and fused core HPLC columns for fast chromatographic analysis of fat-soluble vitamins

Directory of Open Access Journals (Sweden)

Kurdi Said El

2017-06-01

Full Text Available HPLC stationary phases of monolithic and fused core type can be used to achieve fast chromatographic separation as an alternative to UPLC. In this study, monolithic and fused core stationary phases are compared for fast separation of four fat-soluble vitamins. Three new methods on the first and second generation monolithic silica RP-18e columns and a fused core pentafluoro-phenyl propyl column were developed. Application of three fused core columns offered comparable separations of retinyl palmitate, DL-α-tocopheryl acetate, cholecalciferol and menadione in terms of elution speed and separation efficiency. Separation was achieved in approx. 5 min with good resolution (Rs > 5 and precision (RSD ≤ 0.6 %. Monolithic columns showed, however, a higher number of theoretical plates, better precision and lower column backpressure than the fused core column. The three developed methods were successfully applied to separate and quantitate fat-soluble vitamins in commercial products.

Elemental separation in nanocrystalline Cu-Al alloys

Science.gov (United States)

Wang, Y. B.; Liao, X. Z.; Zhao, Y. H.; Cooley, J. C.; Horita, Z.; Zhu, Y. T.

2013-06-01

Nanocrystallization by high-energy severe plastic deformation has been reported to increase the solubility of alloy systems and even to mix immiscible elements to form non-equilibrium solid solutions. In this letter, we report an opposite phenomenon—nanocrystallization of a Cu-Al single-phase solid solution by high-pressure torsion separated Al from the Cu matrix when the grain sizes are refined to tens of nanometers. The Al phase was found to form at the grain boundaries of nanocrystalline Cu. The level of the separation increases with decreasing grain size, which suggests that the elemental separation was caused by the grain size effect.

Issues concerning the determination of solubility products of sparingly soluble crystalline solids. Solubility of HfO2(cr)

International Nuclear Information System (INIS)

Rai, Dhanpat; Kitamura, Akira; Rosso, Kevin M.; Sasaki, Takayuki; Kobayashi, Taishi

2016-01-01

Solubility studies were conducted with HfO 2 (cr) solid as a function HCl and ionic strength ranging from 2.0 to 0.004 mol kg -1 . These studies involved (1) using two different amounts of the solid phase, (2) acid washing the bulk solid phase, (3) preheating the solid phase to 1400 C, and (4) heating amorphous HfO 2 (am) suspensions to 90 C to ascertain whether the HfO 2 (am) converts to HfO 2 (cr) and to determine the solubility from the oversaturation direction. Based on the results of these treatments it is concluded that the HfO 2 (cr) contains a small fraction of less crystalline, but not amorphous, material [HfO 2 (lcr)] and this, rather than the HfO 2 (cr), is the solubility-controlling phase in the range of experimental variables investigated in this study. The solubility data are interpreted using both the Pitzer and SIT models and they provide log 10 K 0 values of -(59.75±0.35) and -(59.48±0.41), respectively, for the solubility product of HfO 2 (lcr)[HfO 2 (lcr) + 2H 2 O ↔ Hf 4+ + 4OH - ]. The log 10 of the solubility product of HfO 2 (cr) is estimated to be < -63. The observation of a small fraction of less crystalline higher solubility material is consistent with the general picture that mineral surfaces are often structurally and/or compositionally imperfect leading to a higher solubility than the bulk crystalline solid. This study stresses the urgent need, during interpretation of solubility data, of taking precautions to make certain that the observed solubility behavior for sparingly-soluble solids is assigned to the proper solid phase.

Data representing two separate LC-MS methods for detection and quantification of water-soluble and fat-soluble vitamins in tears and blood serum

Directory of Open Access Journals (Sweden)

Maryam Khaksari

2017-04-01

Full Text Available Two separate liquid chromatography (LC-mass spectrometry (MS methods were developed for determination and quantification of water-soluble and fat-soluble vitamins in human tear and blood serum samples. The water-soluble vitamin method was originally developed to detect vitamins B1, B2, B3 (nicotinamide, B5, B6 (pyridoxine, B7, B9 and B12 while the fat-soluble vitamin method detected vitamins A, D3, 25(OHD3, E and K1. These methods were then validated with tear and blood serum samples. In this data in brief article, we provide details on the two LC-MS methods development, methods sensitivity, as well as precision and accuracy for determination of vitamins in human tears and blood serum. These methods were then used to determine the vitamin concentrations in infant and parent samples under a clinical study which were reported in "Determination of Water-Soluble and Fat-Soluble Vitamins in Tears and Blood Serum of Infants and Parents by Liquid Chromatography/Mass Spectrometry DOI:10.1016/j.exer.2016.12.007 [1]". This article provides more details on comparison of vitamin concentrations in the samples with the ranges reported in the literature along with the medically accepted normal ranges. The details on concentrations below the limits of detection (LOD and limits of quantification (LOQ are also discussed. Vitamin concentrations were also compared and cross-correlated with clinical data and nutritional information. Significant differences and strongly correlated data were reported in [1]. This article provides comprehensive details on the data with slight differences or slight correlations.

Data representing two separate LC-MS methods for detection and quantification of water-soluble and fat-soluble vitamins in tears and blood serum.

Science.gov (United States)

Khaksari, Maryam; Mazzoleni, Lynn R; Ruan, Chunhai; Kennedy, Robert T; Minerick, Adrienne R

2017-04-01

Two separate liquid chromatography (LC)-mass spectrometry (MS) methods were developed for determination and quantification of water-soluble and fat-soluble vitamins in human tear and blood serum samples. The water-soluble vitamin method was originally developed to detect vitamins B 1 , B 2 , B 3 (nicotinamide), B 5 , B 6 (pyridoxine), B 7 , B 9 and B 12 while the fat-soluble vitamin method detected vitamins A, D 3 , 25(OH)D 3, E and K 1 . These methods were then validated with tear and blood serum samples. In this data in brief article, we provide details on the two LC-MS methods development, methods sensitivity, as well as precision and accuracy for determination of vitamins in human tears and blood serum. These methods were then used to determine the vitamin concentrations in infant and parent samples under a clinical study which were reported in "Determination of Water-Soluble and Fat-Soluble Vitamins in Tears and Blood Serum of Infants and Parents by Liquid Chromatography/Mass Spectrometry DOI:10.1016/j.exer.2016.12.007 [1]". This article provides more details on comparison of vitamin concentrations in the samples with the ranges reported in the literature along with the medically accepted normal ranges. The details on concentrations below the limits of detection (LOD) and limits of quantification (LOQ) are also discussed. Vitamin concentrations were also compared and cross-correlated with clinical data and nutritional information. Significant differences and strongly correlated data were reported in [1]. This article provides comprehensive details on the data with slight differences or slight correlations.

Origin of Reversible Photoinduced Phase Separation in Hybrid Perovskites.

Science.gov (United States)

Bischak, Connor G; Hetherington, Craig L; Wu, Hao; Aloni, Shaul; Ogletree, D Frank; Limmer, David T; Ginsberg, Naomi S

2017-02-08

The distinct physical properties of hybrid organic-inorganic materials can lead to unexpected nonequilibrium phenomena that are difficult to characterize due to the broad range of length and time scales involved. For instance, mixed halide hybrid perovskites are promising materials for optoelectronics, yet bulk measurements suggest the halides reversibly phase separate upon photoexcitation. By combining nanoscale imaging and multiscale modeling, we find that the nature of halide demixing in these materials is distinct from macroscopic phase separation. We propose that the localized strain induced by a single photoexcited charge interacting with the soft, ionic lattice is sufficient to promote halide phase separation and nucleate a light-stabilized, low-bandgap, ∼8 nm iodide-rich cluster. The limited extent of this polaron is essential to promote demixing because by contrast bulk strain would simply be relaxed. Photoinduced phase separation is therefore a consequence of the unique electromechanical properties of this hybrid class of materials. Exploiting photoinduced phase separation and other nonequilibrium phenomena in hybrid materials more generally could expand applications in sensing, switching, memory, and energy storage.

Metal ion separations using reactive membranes

International Nuclear Information System (INIS)

Way, J.D.

1993-01-01

A membrane is a barrier between two phases. If one component of a mixture moves through the membrane faster than another mixture component, a separation can be accomplished. Membranes are used commercially for many applications including gas separations, water purification, particle filtration, and macromolecule separations (Abelson). There are two points to note concerning this definition. First, a membrane is defined based on its function, not the material used to make the membrane. Secondly, a membrane separation is a rate process. The separation is accomplished by a driving force, not by equilibrium between phases. Liquids that are immiscible with the feed and product streams can also be used as membrane materials. Different solutes will have different solubilities and diffusion coefficients in a liquid. The product of the diffusivity and the solubility is known as the permeability coefficient, which is proportional to the solute flux. Differences in permeability coefficient will produce a separation between solutes at constant driving force. Because the diffusion coefficients in liquids are typically orders of magnitude higher than in polymers, a larger flux can be obtained. Further enhancements can be accomplished by adding a nonvolatile complexation agent to the liquid membrane. One can then have either coupled or facilitated transport of metal ions through a liquid membrane. The author describes two implementations of this concept, one involving a liquid membrane supported on a microporous membrane, and the other an emulsion liquid membrane, where separation occurs to internal receiving phases. Applications and costing studies for this technology are reviewed, and a brief summary of some of the problems with liquid membranes is presented

Issues concerning the determination of solubility products of sparingly soluble crystalline solids. Solubility of HfO{sub 2}(cr)

Energy Technology Data Exchange (ETDEWEB)

Rai, Dhanpat [Rai Enviro-Chem, LLC, Yachats, OR (United States); Kitamura, Akira [Japan Atomic Energy Agency, Ibaraki (Japan); Rosso, Kevin M. [Pacific Northwest National Laboratory, Richland, WA (United States); Sasaki, Takayuki; Kobayashi, Taishi [Kyoto Univ. (Japan)

2016-11-01

Solubility studies were conducted with HfO{sub 2}(cr) solid as a function HCl and ionic strength ranging from 2.0 to 0.004 mol kg{sup -1}. These studies involved (1) using two different amounts of the solid phase, (2) acid washing the bulk solid phase, (3) preheating the solid phase to 1400 C, and (4) heating amorphous HfO{sub 2}(am) suspensions to 90 C to ascertain whether the HfO{sub 2}(am) converts to HfO{sub 2}(cr) and to determine the solubility from the oversaturation direction. Based on the results of these treatments it is concluded that the HfO{sub 2}(cr) contains a small fraction of less crystalline, but not amorphous, material [HfO{sub 2}(lcr)] and this, rather than the HfO{sub 2}(cr), is the solubility-controlling phase in the range of experimental variables investigated in this study. The solubility data are interpreted using both the Pitzer and SIT models and they provide log{sub 10} K{sup 0} values of -(59.75±0.35) and -(59.48±0.41), respectively, for the solubility product of HfO{sub 2}(lcr)[HfO{sub 2}(lcr) + 2H{sub 2}O ↔ Hf{sup 4+} + 4OH{sup -}]. The log{sub 10} of the solubility product of HfO{sub 2}(cr) is estimated to be < -63. The observation of a small fraction of less crystalline higher solubility material is consistent with the general picture that mineral surfaces are often structurally and/or compositionally imperfect leading to a higher solubility than the bulk crystalline solid. This study stresses the urgent need, during interpretation of solubility data, of taking precautions to make certain that the observed solubility behavior for sparingly-soluble solids is assigned to the proper solid phase.

Determination of fat- and water-soluble vitamins by supercritical fluid chromatography: A review.

Science.gov (United States)

Tyśkiewicz, Katarzyna; Dębczak, Agnieszka; Gieysztor, Roman; Szymczak, Tomasz; Rój, Edward

2018-01-01

Vitamins are compounds that take part in all basic functions of an organism but also are subject of number of studies performed by different researchers. Two groups of vitamins are distinguished taking into consideration their solubility. Chromatography with supercritical CO 2 has found application in the determination, separation, and quantitative analyses of both fat- and water-soluble vitamins. The methods of vitamins separation have developed and improved throughout the years. Both groups of compounds were separated using supercritical fluid chromatography with different detection on different stationary phases. The main aim of this review is to provide an overview of the studies of vitamins separation that have been determined so far. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Phase Separation and Crystallization in soda-lime borosilicate glass enriched in MoO{sub 3} studied by in situ Raman spectroscopy at high temperature

Energy Technology Data Exchange (ETDEWEB)

Magnin, M.; Schuller, S.; Advocat, T. [CEA Valrho, DEN/DTCD/SCDV, Laboratoire d' Etude de Base sur les Verres, BP 17171, 30207 Bagnols-sur-Ceze Cedex (France); Caurant, D.; Majerus, O. [Laboratoire de Chimie de la Matiere Condensee de Paris- LCMCP - UMR-CNRS 7574, Ecole Nationale Superieure de Chimie de Paris - ENSCP, Paristech, 75231 Paris (France); Ligny, D. de [Laboratoire de Physico-Chimie des Materiaux Luminescents- LPCML - UMR-CNRS 5620, Universite Claude Bernard Lyon1, 69622 Villeurbanne (France)

2008-07-01

Phase separation and crystallisation processes may arise in molten glass when the MoO{sub 3} content exceeds its solubility limit. Molybdenum combined with other elements such as alkali and alkaline-earth may form crystalline molybdates, known as 'yellow phases' in nuclear glasses. In order to establish the sequence of phase separation and crystallization processes occurring during the cooling of the melt, a non-radioactive simplified glass composition was chosen in the SiO{sub 2}-B{sub 2}O{sub 3}-Na{sub 2}O-CaO system, with 2 mol.% MoO{sub 3}. Various cooling scenarios were tested: cooling by air blowing, quenching between two copper plates and cooling on metallic plate. The resulting glass specimens were then characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and Raman spectroscopy in temperature. These observations made it possible to determine the sequence and the appearance temperature of phenomena upon cooling: first, a phase separation occurs, (small droplets dispersed in the molten glass) followed by molybdates crystallization inside the droplets. (authors)

Phase separation in Sr doped BiMnO3

International Nuclear Information System (INIS)

Li Guan-Nan; Gao Qing-Qing; Luo Jun; Liu Guang-Yao; Liang Jing-Kui; Rao Guang-Hui; Huang Qing-Zhen; Li Jing-Bo

2014-01-01

Phase separation in Sr doped BiMnO 3 (Bi 1−x Sr x MnO 3 , x = 0.4−0.6) was studied by means of temperature-dependent high-resolution neutron powder diffraction (NPD), high resolution X-ray powder diffraction (XRD), and physical property measurements. All the experiments indicate that a phase separation occurs at the temperature coinciding with the reported charge ordering temperature (T CO ) in the literature. Below the reported T CO , both the phases resulting from the phase separation crystallize in the orthorhombically distorted perovskite structure with space group Imma. At lower temperature, these two phases order in the CE-type antiferromagnetic structure and the A-type antiferromagnetic structure, respectively. However, a scrutiny of the high-resolution NPD and XRD data at different temperatures and the electron diffraction experiment at 300 K did not manifest any evidence of a long-range charge ordering (CO) in our investigated samples, suggesting that the anomalies of physical properties such as magnetization, electric transport, and lattice parameters at the T CO might be caused by the phase separation rather than by a CO transition

Stress-Triggered Phase Separation Is an Adaptive, Evolutionarily Tuned Response

Energy Technology Data Exchange (ETDEWEB)

Riback, Joshua A.; Katanski, Christopher D.; Kear-Scott, Jamie L.; Pilipenko, Evgeny V.; Rojek, Alexandra E.; Sosnick, Tobin R.; Drummond, D. Allan

2017-03-01

In eukaryotic cells, diverse stresses trigger coalescence of RNA-binding proteins into stress granules. In vitro, stress-granule-associated proteins can demix to form liquids, hydrogels, and other assemblies lacking fixed stoichiometry. Observing these phenomena has generally required conditions far removed from physiological stresses. We show that poly(A)-binding protein (Pab1 in yeast), a defining marker of stress granules, phase separates and forms hydrogels in vitro upon exposure to physiological stress conditions. Other RNA-binding proteins depend upon low-complexity regions (LCRs) or RNA for phase separation, whereas Pab1’s LCR is not required for demixing, and RNA inhibits it. Based on unique evolutionary patterns, we create LCR mutations, which systematically tune its biophysical properties and Pab1 phase separation in vitro and in vivo. Mutations that impede phase separation reduce organism fitness during prolonged stress. Poly(A)-binding protein thus acts as a physiological stress sensor, exploiting phase separation to precisely mark stress onset, a broadly generalizable mechanism.

Phase separation in lipid bilayers triggered by low pH

International Nuclear Information System (INIS)

Suresh, Swetha; Edwardson, J. Michael

2010-01-01

Research highlights: → Lipid bilayers have been imaged by atomic force microscopy (AFM). → At pH 5 phase separation occurs in lipid bilayers containing mixed acyl chains. → Phase separation does not occur when lipids have only unsaturated chains. → Phase separation might drive protein clustering during endocytosis. -- Abstract: Endocytosis involves the capture of membrane from the cell surface in the form of vesicles, which become rapidly acidified to about pH 5. Here we show using atomic force microscopy (AFM) imaging that this degree of acidification triggers phase separation in lipid bilayers containing mixed acyl chains (e.g. palmitoyl/oleoyl) or complex mixtures (e.g. total brain extract) but not in bilayers containing only lipids with unsaturated chains (e.g. dioleoyl). Since mixed-chain lipids are major constituents of the outer leaflet of the plasma membrane, the type of phase separation reported here might support protein clustering and signaling during endocytosis.

Neptunium immobilization and recovery using phase separated glasses

International Nuclear Information System (INIS)

Meaker, T.F.

1997-01-01

A phase separated (amorphous) glass has been developed which allows very efficient recovery of +4 valence actinides. The total amount of crystal formation in a heat treated vycor-type glass can be controlled with time, temperature and loading. Heat treatments at lower temperatures and for less time inhibit crystal formation while still allowing significant phase separation. If the Thorium loading exceeds 10 weight percent oxide, crystal formation during heat treatment may not be avoided. The total amount of crystal growth has a direct affect on thorium leachability. An increase in crystal formation limits the Th recovery significantly. High thorium loaded glasses (15 weight percent) with heat treatments (increased crystal formation) leach at approximately the same rate as non-heat treated glasses. A phase separated (amorphous) glass has been produced using thorium as a surrogate for neptunium. Two different homogeneous vycor compositions targeting 10 and 15 weight percent thorium oxide have been processed, heat treated and leached with concentrated nitric acid at 110 degrees C. Thorium recovery rates have been shown to be considerably better when the glass has been heat treated inducing phase separation that is relatively crystal free. Non-heat treated and crystalline (due to heat treatment) glasses have similar Th recovery rates with respect to surface area. Phase separated amorphous samples were found to have significantly higher thorium concentrations in the leachate compared to non-heat treated and crystalline glasses for all mesh sizes. All glasses had increased thorium concentration in the leachate as surface area increased

Mass transfer apparatus and method for separation of gases

Energy Technology Data Exchange (ETDEWEB)

Blount, Gerald C.; Gorensek, Maximilian Boris; Hamm, Luther L.

2018-01-16

A process and apparatus for separating components of a source gas is provided in which more soluble components of the source gas are dissolved in an aqueous solvent at high pressure. The system can utilize hydrostatic pressure to increase solubility of the components of the source gas. The apparatus includes gas recycle throughout multiple mass transfer stages to improve mass transfer of the targeted components from the liquid to gas phase. Separated components can be recovered for use in a value added application or can be processed for long-term storage, for instance in an underwater reservoir.

Potential for radionuclide immobilization in the EBS/NFE: solubility limiting phases for neptunium, plutonium, and uranium

Energy Technology Data Exchange (ETDEWEB)

Rard, J. A., LLNL

1997-10-01

Retardation and dispersion in the far field of radionuclides released from the engineered barrier system/near field environment (EBS/NFE) may not be sufficient to prevent regulatory limits being exceeded at the accessible environment. Hence, a greater emphasis must be placed on retardation and/or immobilization of radionuclides in the EBS/NFE. The present document represents a survey of radionuclide-bearing solid phases that could potentially form in the EBS/NFE and immobilize radionuclides released from the waste package and significantly reduce the source term. A detailed literature search was undertaken for experimental solubilities of the oxides, hydroxides, and various salts of neptunium, plutonium, and uranium in aqueous solutions as functions of pH, temperature, and the concentrations of added electrolytes. Numerous solubility studies and reviews were identified and copies of most of the articles were acquired. However, this project was only two months in duration, and copies of some the identified solubility studies could not be obtained at short notice. The results of this survey are intended to be used to assess whether a more detailed study of identified low- solubility phase(s) is warranted, and not as a data base suitable for predicting radionuclide solubility. The results of this survey may also prove useful in a preliminary evaluation of the efficacy of incorporating chemical additives to the EBS/NFE that will enhance radionuclide immobilization.

Study of phase separation and crystallization phenomena in soda-lime borosilicate glass enriched in MoO3

International Nuclear Information System (INIS)

Magnin, M.

2009-09-01

Molybdenum oxide immobilization (MoO 3 , as fission product) is one of the major challenges in the nuclear glass formulation issues for high level waste solutions conditioning since many years, these solutions arising from spent nuclear fuel reprocessing. Phase separation and crystallisation processes may arise in molten glass when the MoO 3 content is higher than its solubility limit that may depend on glass composition. Molybdenum combined with other elements such as alkali and alkaline-earth may form crystalline molybdates, known as 'yellow phases' in nuclear glasses which may decrease the glass durability. In order to confine high level wastes (HLW) such as the fission product solutions arising from the reprocessing of high burn-up UOX-type nuclear spent fuels, a new glass composition (HLW glass) is being optimized. This work is devoted to the study of the origin and the mechanism of phase separation and crystallization phenomena induced by molybdenum oxide incorporation in the HLW glass. From microstructural and structural point of view, the molybdenum oxide behavior was studied in glass compositions belonging to the SiO 2 -B 2 O 3 - Na 2 O-CaO simplified system which constituted basis for the HLW glass formulation. The structural role of molybdenum oxide in borosilicate network explaining the phase separation and crystallization tendency was studied through the coupling of structural ( 95 Mo, 29 Si, 11 B, 23 Na MAS NMR, XRD) and microstructural (SEM, HRTEM) analysis techniques. The determination of phase separation (critical temperature) and crystallization (liquidus temperature) appearance temperatures by in situ viscosimetry and Raman spectroscopy experiments allowed us to propose a transformation scenario during melt cooling. These processes and the nature of the crystalline phases formed (CaMoO 4 , Na 2 MoO 4 ) that depend on the evolution of MoO 3 , CaO and B 2 O 3 contents were correlated with changes of sodium and calcium cations proportions in the

Double-antibody solid-phase radioimmunoassay: a simplified phase-separation procedure applied to various ligands

International Nuclear Information System (INIS)

Tevaarwerk, G.J.M.; Boyle, D.A.; Hurst, C.J.; Anguish, I.; Uksik, P.

1980-01-01

The purpose was to develop a simplified and reliable method of separating free from antibody-bound ligand using a precipitating antibody linked to a cellulose derivative. Dose-response curves and control sera were set up in parallel for various pituitary and placental polypeptides, steroid hormones, insulin, glucagon, triiodothyronine, thyroxine, angiotensin I, calcitonin, gastrin, cyclic AMP, and digoxin. After first-antibody reactions had reached equilibrium, free and bound ligand were separated using a double-antibody solid-phase system in parallel with conventional methods, including dextran-coated charcoal, double-antibody precipitation, single-antibody solid phase, organic solvents, salt precipitation, and anion-exchange resins. The effect of variations in temperature, incubation time, protein content, pH, and amount of separating material added were studied. The results showed that separation was complete within 1 hr for small ligand molecules and within 2 hr for larger ones. Dose-response curves and control-sera results closely paralleled those obtained with conventional methods. The method was not affected by moderate variations in incubation variables. Nonspecific binding was less than 3% in all assays, while intra-assay and interassay coefficients of variation were similar to those obtained with conventional phase-separation methods. It is concluded that the method is a simple and rapid alternative phase-separation system. It has the advantage of being free from common nonspecific intersample variations, and can be applied to any assay system based on rabbit or guinea pig antibodies without preliminay time- or reagent-consuming titration or adjustments to establish optimum phase-separating conditions

Phase separation in the nonequilibrium Verwey transition in magnetite

Science.gov (United States)

Randi, F.; Vergara, I.; Novelli, F.; Esposito, M.; Dell'Angela, M.; Brabers, V. A. M.; Metcalf, P.; Kukreja, R.; Dürr, H. A.; Fausti, D.; Grüninger, M.; Parmigiani, F.

2016-02-01

We present equilibrium and out-of-equilibrium studies of the Verwey transition in magnetite. In the equilibrium optical conductivity, we find a steplike change at the phase transition for photon energies below about 2 eV. The possibility of triggering a nonequilibrium transient metallic state in insulating magnetite by photo excitation was recently demonstrated by an x-ray study. Here we report a full characterization of the optical properties in the visible frequency range across the nonequilibrium phase transition. Our analysis of the spectral features is based on a detailed description of the equilibrium properties. The out-of-equilibrium optical data bear the initial electronic response associated to localized photoexcitation, the occurrence of phase separation, and the transition to a transient metallic phase for excitation density larger than a critical value. This allows us to identify the electronic nature of the transient state, to unveil the phase transition dynamics, and to study the consequences of phase separation on the reflectivity, suggesting a spectroscopic feature that may be generally linked to out-of-equilibrium phase separation.

Numerical Simulation on Flow Field of Oilfield Three-Phase Separator

Directory of Open Access Journals (Sweden)

Yong-tu Liang

2013-01-01

Full Text Available The conventional measurement method can no longer guarantee the accuracy requirement after the oilfield development entering high water cut stage, due to the water content and gas phase in the flow. In order to overcome the impact of measurement deviation the oilfield production management, the flow field of three-phase separator is studied numerically in this paper using Fluent 6.3.26. Taking into consideration the production situation of PetroChina Huabei Oilfield and the characteristics of three-phase separator, the effect of internal flow status as well as other factors such as varying flow rate, gas fraction, and water content on the separation efficiency is analyzed. The results show that the separation efficiencies under all operation conditions are larger than 95%, which satisfy the accuracy requirement and also provide the theoretical foundation for the application of three-phase separators at oilfields.

Spin Filtering in Epitaxial Spinel Films with Nanoscale Phase Separation

KAUST Repository

Li, Peng

2017-05-08

The coexistence of ferromagnetic metallic phase and antiferromagnetic insulating phase in nanoscaled inhomogeneous perovskite oxides accounts for the colossal magnetoresistance. Although the model of spin-polarized electron transport across antiphase boundaries has been commonly employed to account for large magnetoresistance (MR) in ferrites, the magnetic anomalies, the two magnetic phases and enhanced molecular moment, are still unresolved. We observed a sizable MR in epitaxial spinel films (NiCo2O4-δ) that is much larger than that commonly observed in spinel ferrites. Detailed analysis reveals that this MR can be attributed to phase separation, in which the perfect ferrimagnetic metallic phase and ferrimagnetic insulating phase coexist. The magnetic insulating phase plays an important role in spin filtering in these phase separated spinel oxides, leading to a sizable MR effect. A spin filtering model based on Zeeman effect and direct tunneling is developed to account for MR of the phase separated films.

A level-set method for two-phase flows with soluble surfactant

Science.gov (United States)

Xu, Jian-Jun; Shi, Weidong; Lai, Ming-Chih

2018-01-01

A level-set method is presented for solving two-phase flows with soluble surfactant. The Navier-Stokes equations are solved along with the bulk surfactant and the interfacial surfactant equations. In particular, the convection-diffusion equation for the bulk surfactant on the irregular moving domain is solved by using a level-set based diffusive-domain method. A conservation law for the total surfactant mass is derived, and a re-scaling procedure for the surfactant concentrations is proposed to compensate for the surfactant mass loss due to numerical diffusion. The whole numerical algorithm is easy for implementation. Several numerical simulations in 2D and 3D show the effects of surfactant solubility on drop dynamics under shear flow.

Effect of atomic disorder on the magnetic phase separation

Science.gov (United States)

Groshev, A. G.; Arzhnikov, A. K.

2018-05-01

The effect of disorder on the magnetic phase separation between the antiferromagnetic and incommensurate helical and phases is investigated. The study is based on the quasi-two-dimensional single-band Hubbard model in the presence of atomic disorder (the Anderson–Hubbard model). A model of binary alloy disorder is considered, in which the disorder is determined by the difference in energy between the host and impurity atomic levels at a fixed impurity concentration. The problem is solved within the theory of functional integration in static approximation. Magnetic phase diagrams are obtained as functions of the temperature, the number of electrons and impurity concentration with allowance for phase separation. It is shown that for the model parameters chosen, the disorder caused by impurities whose atomic-level energy is greater than that of the host atomic levels, leads to qualitative changes in the phase diagram of the impurity-free system. In the opposite case, only quantitative changes occur. The peculiarities of the effect of disorder on the phase separation regions of the quasi-two-dimensional Hubbard model are discussed.

Phase separation phenomena in branching conduits. Topical report Dec 78-Dec 81

International Nuclear Information System (INIS)

Saba, N.; Lahey, R.T. Jr.

1982-03-01

The analysis of Light Water Reactor (LWR) Loss-of-Coolant Accidents (LOCA's) requires that one be able to accurately calculate the two-phase flow splits in complex, branching conduits. The purpose of this study is to provide a general method for calculating the phase separation in a branching conduit. The degree of phase separation of a two-phase (air/water) mixture flowing through a plexiglas tee test section was measured. In addition, flow visualization, using high speed photography, was performed. The experimental design considerations, error analysis and the dependence of the observed phase separation on global parameters, such as inlet quality, mass flux and separation angle, are discussed. The pressure gradients were measured along the various conduits and the differential pressure was obtained at the tee junction by extrapolation. It was found that the degree of phase separation was quite pronounced, with the vapor phase preferentially separating into the branch. Using these data, a physically-based empirical model was developed with which to calculate the phasic distribution of a subsonic two-phase mixture in the downstream branches of a branching conduit

Solubilities of uranium for TILA-99

International Nuclear Information System (INIS)

Ollila, K.; Ahonen, L.

1998-11-01

This report presents the evaluation of the uranium solubilities in the reference waters of TILA-99. The behaviour of uranium has been discussed separately in the near-field and far-field conditions. The bentonite/groundwater interactions have been considered in the compositions of the fresh and saline near-field reference waters. The far-field groundwaters' compositions include fresh, brackish, saline and very saline, almost brine-type compositions. The pH and redox conditions, as the main parameters affecting the solubilities, are considered. A literature study was made in order to obtain information on the recent dissolution and leaching experiments of UO 2 and spent fuel. The latest literature includes studies on UO 2 solubility under anoxic conditions, in which the methods for simulating the reducing conditions of deep groundwater have been improved. Studies on natural uraninite and its alteration products give a valuable insight into the long-term behaviour of spent fuel. Also the solubility equilibria for some relevant poorly known uranium minerals have been determined. The solubilities of the selected solubility-limiting phases were calculated using the geochemical code, EQ3/6. The NEA database for uranium was the basis for the modelling. The recently extended and updated SR '97 database was used for comparison. The solubility products for uranophane were taken from the latest literature. The recommended values for solubilities were given after a comparison between the calculated solubilities, experimental information and measured concentrations in natural groundwaters. The experiments include several UO 2 dissolution studies in synthetic groundwaters with compositions close to the reference groundwaters. (author)

Solubilities of uranium for TILA-99

Energy Technology Data Exchange (ETDEWEB)

Ollila, K. [VTT Chemical Technology, Espoo (Finland); Ahonen, L. [Geological Survey of Finland, Espoo (Finland)

1998-11-01

This report presents the evaluation of the uranium solubilities in the reference waters of TILA-99. The behaviour of uranium has been discussed separately in the near-field and far-field conditions. The bentonite/groundwater interactions have been considered in the compositions of the fresh and saline near-field reference waters. The far-field groundwaters` compositions include fresh, brackish, saline and very saline, almost brine-type compositions. The pH and redox conditions, as the main parameters affecting the solubilities, are considered. A literature study was made in order to obtain information on the recent dissolution and leaching experiments of UO{sub 2} and spent fuel. The latest literature includes studies on UO{sub 2} solubility under anoxic conditions, in which the methods for simulating the reducing conditions of deep groundwater have been improved. Studies on natural uraninite and its alteration products give a valuable insight into the long-term behaviour of spent fuel. Also the solubility equilibria for some relevant poorly known uranium minerals have been determined. The solubilities of the selected solubility-limiting phases were calculated using the geochemical code, EQ3/6. The NEA database for uranium was the basis for the modelling. The recently extended and updated SR `97 database was used for comparison. The solubility products for uranophane were taken from the latest literature. The recommended values for solubilities were given after a comparison between the calculated solubilities, experimental information and measured concentrations in natural groundwaters. The experiments include several UO{sub 2} dissolution studies in synthetic groundwaters with compositions close to the reference groundwaters. (author) 81 refs.

Membranes as separators of dispersed emulsion phases

OpenAIRE

Lefferts, A.G.

1997-01-01

The reuse or discharge of industrial waste waters, containing small fractions of dispersed oil, requires a purification treatment for which membranes can be used. If only little oil is present, removal of the dispersed phase might be preferable to the more commonly applied removal of the continuous phase. For this purpose dispersed phase separators can be applied, which combine the features of conventional coalescers and membrane filtration. The membrane surface promotes coalescence ...

Phase strength and super lattices

Indian Academy of Sciences (India)

Unknown

much below the solubility limit, so that the short chain molecules do not behave as solvent molecules). Therefore enhanced phase separation and lesser incorporation of. C10-ol (which is however still higher than the value at point B) is responsible for the formation of relatively lesser βo phase and more βm phase at MR ...

Effect of applied strain on phase separation of Fe-28 at.% Cr alloy: 3D phase-field simulation

Science.gov (United States)

Zhu, Lihui; Li, Yongsheng; Liu, Chengwei; Chen, Shi; Shi, Shujing; Jin, Shengshun

2018-04-01

A quantitative simulation of the separation of the α‧ phase in Fe-28 at.% Cr alloy under the effects of applied strain is performed by utilizing a three-dimensional phase-field model. The elongation of the Cr-enriched α‧ phase becomes obvious with the influence of applied uniaxial strain for the phase separation transforms from spinodal decomposition of 700 K to nucleation and growth of 773 K. The applied strain shows a significant influence on the early stage phase separation, and the influence is enlarged with the elevated temperature. The steady-state coarsening with the mechanism of spinodal decomposition is substantially affected by the applied strain for low-temperature aging, while the influence is reduced as the temperature increases and as the phase separation mechanism changes to nucleation and growth. The peak value of particle size distribution decreases, and the PSD for 773 K becomes more widely influenced by the applied strain. The simulation results of separation of the Cr-enriched α‧ phase with the applied strain provide a further understanding of the strain effect on the phase separation of Fe-Cr alloys from the metastable region to spinodal regions.

Lithium isotope separation factors of some two-phase equilibrium systems

International Nuclear Information System (INIS)

Palko, A.A.; Drury, J.S.; Begun, G.M.

1976-01-01

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 6 Li 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

Phase separation in fermionic systems with particle–hole asymmetry

International Nuclear Information System (INIS)

Montorsi, Arianna

2008-01-01

We determine the ground-state phase diagram of a Hubbard Hamiltonian with correlated hopping, which is asymmetric under particle–hole transform. By lowering the repulsive Coulomb interaction U at appropriate filling and interaction parameters, the ground state separates into hole and electron conducting phases: two different wavevectors characterize the system and charge–charge correlations become incommensurate. By further decreasing U another transition occurs at which the hole conducting region becomes insulating, and conventional phase separation takes place. Finally, for negative U the whole system eventually becomes a paired insulator. It is speculated that such behavior could be at the origin of the incommensurate superconducting phase recently discovered in the 1D Hirsch model. The exact phase boundaries are calculated in one dimension. (letter)

Segregative phase separation in aqueous mixtures of polydisperse biopolymers

NARCIS (Netherlands)

Edelman, M.W.

2003-01-01

Keywords: biopolymer, gelatine, dextran, PEO, phase separation, polydispersity, molar mass distribution, SEC-MALLS, CSLM The temperature-composition phase diagram of aqueous solutions of gelatine and dextran, which show liquid/liquid phase segregation, were explored at temperatures above the

Solubility of polyvalent cations in fogwater at an urban site in Strasbourg (France)

Science.gov (United States)

Millet, M.; Wortham, H.; Mirabel, Ph.

The concentrations in the soluble and total (soluble + insoluble) fractions of Mg, Ca, Fe, Mn, Zn, Al, Cd and Pb have been analysed by "inductively coupled plasma (ICP)" in 14 fog events collected in 1992 at an urban site in France (Strasbourg). For each fog event, two droplet size categories (2-6 μm and 5-8 μm) have been collected separately. For the analysis of the polyvalent cations in the soluble and total fractions, an analytical procedure using ICP and filtration on cellulose/PVC filters has been developed. The study of the solubility of some polyvalent cations has shown that two of the most important factors controlling the partitioning between the soluble and insoluble fraction are the nature of the particles and the pH of the fogwater. The influence of pH depended on the element. The solubility of Pb, Cd, Al, Fe, Mg, and Ca were pH dependent whereas, Zn and Mn solubility varied but no relationship with pH existed, ranging between 25 and 100% and 10 and 100%, respectively. On the other hand, Mg, Pb and Ca were predominantly present in the soluble phase, whereas Al was prevalent in the insoluble fraction. In the case of Cd and Fe., the presence in the soluble or insoluble phase depended largely on the fogwater pH.

Steric Pressure among Membrane-Bound Polymers Opposes Lipid Phase Separation.

Science.gov (United States)

Imam, Zachary I; Kenyon, Laura E; Carrillo, Adelita; Espinoza, Isai; Nagib, Fatema; Stachowiak, Jeanne C

2016-04-19

Lipid rafts are thought to be key organizers of membrane-protein complexes in cells. Many proteins that interact with rafts have bulky polymeric components such as intrinsically disordered protein domains and polysaccharide chains. Therefore, understanding the interaction between membrane domains and membrane-bound polymers provides insights into the roles rafts play in cells. Multiple studies have demonstrated that high concentrations of membrane-bound polymeric domains create significant lateral steric pressure at membrane surfaces. Furthermore, our recent work has shown that lateral steric pressure at membrane surfaces opposes the assembly of membrane domains. Building on these findings, here we report that membrane-bound polymers are potent suppressors of membrane phase separation, which can destabilize lipid domains with substantially greater efficiency than globular domains such as membrane-bound proteins. Specifically, we created giant vesicles with a ternary lipid composition, which separated into coexisting liquid ordered and disordered phases. Lipids with saturated tails and poly(ethylene glycol) (PEG) chains conjugated to their head groups were included at increasing molar concentrations. When these lipids were sparse on the membrane surface they partitioned to the liquid ordered phase. However, as they became more concentrated, the fraction of GUVs that were phase-separated decreased dramatically, ultimately yielding a population of homogeneous membrane vesicles. Experiments and physical modeling using compositions of increasing PEG molecular weight and lipid miscibility phase transition temperature demonstrate that longer polymers are the most efficient suppressors of membrane phase separation when the energetic barrier to lipid mixing is low. In contrast, as the miscibility transition temperature increases, longer polymers are more readily driven out of domains by the increased steric pressure. Therefore, the concentration of shorter polymers required

Isotopic separation of nitrogen 15. Influence of the gaseous phase composition

International Nuclear Information System (INIS)

Lacoste, Germain; Routie, Rene; Mahenc, Jean

1977-01-01

A study has been made on the gas phase composition effect on the isotopic separation of nitrogen 15 for the two HNO 3 -NO and N 2 O 3 -NO systems. It was shown that the changes in composition of the gas phases could account for the increase in the overall separation; most accuracy, measurements of isotopic concentration along the separation column and of total enrichment exhibit how important are the reactions of oxydo-reduction between the two phases in such process [fr

A phase-field and electron microscopy study of phase separation in Fe-Cr alloys

Energy Technology Data Exchange (ETDEWEB)

Hedstroem, Peter, E-mail: pheds@kth.se [Materials Science and Engineering, KTH (Royal Institute of Technology), SE-100 44 Stockholm (Sweden); Baghsheikhi, Saeed [Materials Science and Engineering, KTH (Royal Institute of Technology), SE-100 44 Stockholm (Sweden); Liu, Ping [Sandvik Materials Technology, R and D Centre, SE-81181 Sandviken (Sweden); Odqvist, Joakim [Materials Science and Engineering, KTH (Royal Institute of Technology), SE-100 44 Stockholm (Sweden); Sandvik Materials Technology, R and D Centre, SE-81181 Sandviken (Sweden)

2012-02-01

Highlights: Black-Right-Pointing-Pointer Experimental characterization and Phase-field modeling of phase separation in Fe-Cr. Black-Right-Pointing-Pointer Transition from particle-like to spinodal-like structure observed. Black-Right-Pointing-Pointer Structural evolution generates increased hardness. Black-Right-Pointing-Pointer Results in agreement with recent thermodynamic description. Black-Right-Pointing-Pointer Quantitative kinetic modeling must include thermal noise and improved kinetic data. - Abstract: Phase separation in the binary Fe-Cr system, the basis for the entire stainless steel family, is considered responsible for the low temperature embrittlement in ferritic, martensitic and duplex stainless steels. These steels are often used in load-bearing applications with considerable service time at elevated temperature. Thus, understanding the effect of microstructure on mechanical properties and predicting dynamics of phase separation are key issues. In the present work, experimental evaluation of structure and mechanical properties in binary Fe-Cr alloys as well as phase-field modeling, using a new thermodynamic description of Fe-Cr, is conducted. A significant hardening evolution with time is found for alloys aged between 400 and 550 Degree-Sign C, and it can be attributed to phase separation. The decomposed structure changed with increasing Cr content at 500 Degree-Sign C, with a more particle-like structure at 25 wt% Cr and a more spinodal-like structure at 30 wt% Cr. The observed transition of structure agrees with the thermodynamically predicted spinodal, although the transition is expected to be gradual. The phase-field simulations qualitatively agree with experiments. However, to enable accurate quantitative predictions, the diffusional mobilities must be evaluated further and thermal fluctuations as well as 3D diffusion fields must be properly accounted for.

Origin of Reversible Photoinduced Phase Separation in Hybrid Perovskites

Science.gov (United States)

Bischak, Connor G.; Hetherington, Craig L.; Wu, Hao; Aloni, Shaul; Ogletree, D. Frank; Limmer, David T.; Ginsberg, Naomi S.

2017-02-01

Nonequilibrium processes occurring in functional materials can significantly impact device efficiencies and are often difficult to characterize due to the broad range of length and time scales involved. In particular, mixed halide hybrid perovskites are promising for optoelectronics, yet the halides reversibly phase separate when photo-excited, significantly altering device performance. By combining nanoscale imaging and multiscale modeling, we elucidate the mechanism underlying this phenomenon, demonstrating that local strain induced by photo-generated polarons promotes halide phase separation and leads to nucleation of light-stabilized iodide-rich clusters. This effect relies on the unique electromechanical properties of hybrid materials, characteristic of neither their organic nor inorganic constituents alone. Exploiting photo-induced phase separation and other nonequilibrium phenomena in hybrid materials, generally, could enable new opportunities for expanding the functional applications in sensing, photoswitching, optical memory, and energy storage.

Relation between secondary doping and phase separation in PEDOT:PSS films

Energy Technology Data Exchange (ETDEWEB)

Donoval, Martin; Micjan, Michal; Novota, Miroslav; Nevrela, Juraj; Kovacova, Sona; Pavuk, Milan; Juhasz, Peter; Jagelka, Martin; Kovac, Jaroslav; Jakabovic, Jan [Institute of Electronics and Photonics, Slovak University of Technology, Ilkovičova 3, Bratislava 81219 (Slovakia); Cigan, Marek [Institute of Chemistry, Faculty of Natural Science, Comenius University, Mlynska dolina CH-2, Ilkovicova 6, Bratislava 84215 (Slovakia); Weis, Martin, E-mail: martin.weis@stuba.sk [Institute of Electronics and Photonics, Slovak University of Technology, Ilkovičova 3, Bratislava 81219 (Slovakia)

2017-02-15

Highlights: • Surface morphology of highly conductive polymer was investigated. • Phase separation due to secondary doping is an origin of conductivity enhancement. • Phase separation is not dependent on secondary dopant type. - Abstract: Conductive copolymer poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) has been proposed as an alternative to transparent conductive oxides because of its flexibility, transparency, and low-cost production. Four different secondary dopants, namely N,N-dimethylformamide, ethyleneglycol, sorbitol, and dimethyl sulfoxide, have been used to improve the conductivity. The relation between the structure changes and conductivity enhancement is studied in detail. Atomic force microscopy study of the thin film surface reveals the phase separation of PEDOT and PSS. We demonstrate that secondary doping induces the phase separation as well as the conductivity enhancement.

The on-line graph processing study on phase separation of two-phase flow in T-tube

International Nuclear Information System (INIS)

Qian Yong; Xu Jijun; Yang Zhilin; Chen Yifen

1997-01-01

The on-line graph processing measure system is equipped with and experimental study of phase separation of air-water bubbly flow in the horizontal T-junction is carried out. For the first time, the author have found and defined the new type of complete phase separation, by the visual experiment, which shows that under certain conditions, the air flow entering the T junction will flow into the run outlet completely, which had never been reported in the literature Also, the pressure wave feed back effect and the branch bubble flow reorganization effect were found and analyzed. The complexity of this phase separation phenomenon in the T junction has been further revealed via the on-line graph processing technology. Meanwhile the influences of the inlet mass flow rate W1, the inlet mass quality X1, and the mass extraction rate G3/G1 on phase separation were analyzed

Cell-free soluble-phase radioimmunoassay for Thy-1 antigen

Energy Technology Data Exchange (ETDEWEB)

Shalev, A.; Zuckerman, F. (Ben-Gurion Univ. of the Negev, Beersheba (Israel))

1983-12-01

A cell-free, soluble-phase, radioimmunoassay has been developed for Thy-1 antigen. The method is based on immunoprecipitation of radiolabelled Thy-1 molecules with specific antibodies, antiimmunoglobulin serum and polyethyleneglycol (PEG). The method can be used with convenience to screen for the presence of Thy-1 in various fluids as well as on cell surfaces for qualitative or quantitative purposes. Presence of antibodies or autoantibodies against Thy-1 can also be detected specifically. Evidence that the dog, carp, hamster and goldfish carry Thy-1-like molecules on neuronal (brain) cells is demonstrated by this method.

Pinning of phase separation of aqueous solution of hydroxypropylmethylcellulose by gelation

Science.gov (United States)

Kita, Rio; Kaku, Takeshi; Kubota, Kenji; Dobashi, Toshiaki

1999-08-01

Opalescence of the aqueous solution of hydroxypropylmethylcellulose (HPMC) induced by heating has been studied in terms of the phase diagram and the phase separation dynamics. The cloud point curve and the sol-to-gel transition curve intersected with each other at about 55 °C. Just above the cloud-point curve at which the spinodal curve has its minimum, a ring-like scattering pattern appeared corresponding to the spinodal decomposition. Temporal growth of the scattering function in the course of phase separation was studied by a time-resolved light scattering technique. The gelation pinned the phase separation (spinodal decomposition) of the aqueous HPMC solution.

Coal liquefaction process streams characterization and evaluation: Application of liquid chromatographic separation methods to THF-soluble portions of integrated two-stage coal liquefaction resids

Energy Technology Data Exchange (ETDEWEB)

Green, J.B.; Pearson, C.D.; Young, L.L.; Green, J.A. [National Inst. for Petroleum and Energy Research, Bartlesville, OK (United States)

1992-05-01

This study demonstrated the feasibility of using non-aqueous ion exchange liquid chromatography (NIELC) for the examination of the tetrahydrofuran (THF)-soluble distillation resids and THF-soluble whole oils derived from direct coal liquefaction. The technique can be used to separate the material into a number of acid, base, and neutral fractions. Each of the fractions obtained by NIELC was analyzed and then further fractionated by high-performance liquid chromatography (HPLC). The separation and analysis schemes are given in the accompanying report. With this approach, differences can be distinguished among samples obtained from different process streams in the liquefaction plant and among samples obtained at the same sampling location, but produced from different feed coals. HPLC was directly applied to one THF-soluble whole process oil without the NIELC preparation, with limited success. The direct HPLC technique used was directed toward the elution of the acid species into defined classes. The non-retained neutral and basic components of the oil were not analyzable by the direct HPLC method because of solubility limitations. Sample solubility is a major concern in the application of these techniques.

On the phase form of a deformation quantization with separation of variables

Science.gov (United States)

Karabegov, Alexander

2016-06-01

Given a star product with separation of variables on a pseudo-Kähler manifold, we obtain a new formal (1, 1)-form from its classifying form and call it the phase form of the star product. The cohomology class of a star product with separation of variables equals the class of its phase form. We show that the phase forms can be arbitrary and they bijectively parametrize the star products with separation of variables. We also describe the action of a change of the formal parameter on a star product with separation of variables, its formal Berezin transform, classifying form, phase form, and canonical trace density.

Prediction of Phase Separation of Immiscible Ga-Tl Alloys

Science.gov (United States)

Kim, Yunkyum; Kim, Han Gyeol; Kang, Youn-Bae; Kaptay, George; Lee, Joonho

2017-06-01

Phase separation temperature of Ga-Tl liquid alloys was investigated using the constrained drop method. With this method, density and surface tension were investigated together. Despite strong repulsive interactions, molar volume showed ideal mixing behavior, whereas surface tension of the alloy was close to that of pure Tl due to preferential adsorption of Tl. Phase separation temperatures and surface tension values obtained with this method were close to the theoretically calculated values using three different thermodynamic models.

Experimental density, viscosity, interfacial tension and water solubility of ethyl benzene-α-methyl benzyl alcohol–water system

International Nuclear Information System (INIS)

Barega, Esayas W.; Zondervan, Edwin; Haan, André B. de

2013-01-01

Highlights: • Properties were measured for MBA (methyl benzyl alcohol)-EB (ethyl benzene)-water. • MBA concentration was found to influence all the properties strongly. • The water solubility, density, and viscosity increased at high MBA concentration. • The interfacial tension decreased sharply at high MBA concentration. • MBA dictates the phase separation and mass transfer of the ternary system. -- Abstract: Density, viscosity, interfacial tension, and water solubility were measured for the (α-methyl benzyl alcohol (MBA) + Ethyl benzene (EB)) system at different concentrations of MBA in contact with water and sodium hydroxide solution (0.01 mol · kg −1 ) as aqueous phases. The properties were measured to identify the component which plays a governing role in changing the physical properties relevant to mass transfer and phase separation of the ternary system. The concentration of MBA was found to be the major factor influencing all the properties. The water solubility, the density, and the viscosity increased notably at higher concentrations of MBA; while, the interfacial tension decreased strongly. The use of 0.01 mol · kg −1 NaOH as an aqueous phase resulted in a decrease of the interfacial tension and a minor decrease in the water solubility. The density data were correlated using a quadratic mixing rule to describe the influence of concentration at any temperature. The viscosity data are correlated using the Nissan and Grunberg and Katti-Chaudhri equations. The Szyzkowski’s equation was used to correlate the interfacial tension data. The water solubility data were described using an exponential relationship. All the correlations described the experimental physical property data adequately

Kinetic measurements of the hydrolytic degradation of cefixime: effect of Captisol complexation and water-soluble polymers.

Science.gov (United States)

Mallick, Subrata; Mondal, Arijit; Sannigrahi, Santanu

2008-07-01

We have taken kinetic measurements of the hydrolytic degradation of cefixime, and have studied the effect of Captisol complexation and water-soluble polymers on that degradation. The phase solubility of cefixime in Captisol was determined. Kinetic measurements were carried out as a function of pH and temperature. High-performance liquid chromatography (HPLC) was performed to assay all the samples of phase-solubility analysis and kinetic measurements. Chromatographic separation of the degradation products was also performed by HPLC. FT-IR spectroscopy was used to investigate the presence of any interaction between cefixime and Captisol and soluble polymer. The phase-solubility study showed A(L)-type behaviour. The pH-rate profile of cefixime exhibited a U-shaped profile whilst the degradation of cefixime alone was markedly accelerated with elevated temperature. A strong stabilizing influence of the cefixime-Captisol complexation and hypromellose was observed against aqueous mediated degradation, as compared with povidone and macrogol. The unfavourable effect of povidone and macrogol may have been due to the steric hindrance, which prevented the guest molecule from entering the cyclodextrin cavity, whereas hypromellose did not produce any steric hindrance.

Phase separation of X-irradiated lenses of rabbit

International Nuclear Information System (INIS)

Clark, J.I.; Giblin, F.J.; Reddy, V.N.; Benedek, G.B.

1982-01-01

The phase separation temperature (Tcat) was studied as a function of time (age) after the administration of a single dose of radiation (2000 rad), which induces cataract in the rabbit lens. In the normal unirradiated lens, Tcat decreases linearly with age at a rate (DTcat/dt) approximately 2.2 degrees/week. In the irradiated lens, Tcat initially decreases with age much less than the normal lens, then rises sharply with age at the time of the appearance of opacity in the living rabbit eye. We suggest that the phase separation temperature may serve as a sensitive and early indicator of cataractogenic processes in the lens

Concurrent phase separation and clustering in the ferrite phase during low temperature stress aging of duplex stainless steel weldments

International Nuclear Information System (INIS)

Zhou, J.; Odqvist, J.; Thuvander, M.; Hertzman, S.; Hedström, P.

2012-01-01

The concurrent phase separation and clustering of alloying elements in the ferrite phase of duplex stainless steel weldments after stress aging at 325 °C have been investigated by atom probe tomography analysis. Both phase separation, into Fe-rich and Cr-rich ferrite, and solute clustering were observed. Phase separation in the heat-affected zone (HAZ) is most pronounced in the high alloyed SAF 2507, followed by SAF 2205 and SAF 2304. Moreover Cu clustering was observed in the HAZ of SAF 2507. However, decomposition in the weld bead (25.10.4L) was more pronounced than in the HAZs, with both phase separation and clustering of Ni–Mn–Si–Cu. The observed differences in the decomposition behaviors in the HAZ and weld bead can be attributed to the high Ni content and the characteristic microstructure of the weld bead with high internal strains. In addition, an applied tensile stress during aging of weldments has been found to further promote the kinetics of phase separation and clustering.

Continuous Hydrolysis and Liquid–Liquid Phase Separation of an Active Pharmaceutical Ingredient Intermediate Using a Miniscale Hydrophobic Membrane Separator

DEFF Research Database (Denmark)

Cervera Padrell, Albert Emili; Morthensen, Sofie Thage; Lewandowski, Daniel Jacob

2012-01-01

Continuous hydrolysis of an active pharmaceutical ingredient intermediate, and subsequent liquid–liquid (L-L) separation of the resulting organic and aqueous phases, have been achieved using a simple PTFE tube reactor connected to a miniscale hydrophobic membrane separator. An alkoxide product......, obtained in continuous mode by a Grignard reaction in THF, reacted with acidic water to produce partially miscible organic and aqueous phases containing Mg salts. Despite the partial THF–water miscibility, the two phases could be separated at total flow rates up to 40 mL/min at different flow ratios, using...

Toughened cyanate ester alloys via reaction-induced phase separation; Hanno yuhatsugataso bunkai ni yoru taishogekisei cyanate ester alloy

Energy Technology Data Exchange (ETDEWEB)

Hirohata, T.; Kuroda, M.; Nishimura, A. [Sumitomo Electric Industries, Ltd., Osaka (Japan); Inoue, T. [Tokyo Institute of Technology, Tokyo (Japan)

1998-03-15

For the purpose of toughening the matrices of fiber-reinforced plastics (FRPs), the effect of thermosetting/thermoplastic polymer alloys based on cyanate ester alloys is investigated. In the experiment, materials are heated and then allowed to set, which are mixtures of 87.0-43.5wt% of cyanate ester resin, 0-43.5wt% of epoxy resin, and 13.0wt% of soluble polyimide. FRP properties are examined by measuring the after-shock compressive strength, flexural elasticity and flaxural strength, and by performing morphology observation. It is then found that a cyanate ester/soluble polyimide system forms a polymer alloy with phase separation, that its glass transition temperature does not drop, and that the rupture strength is increased approximately twice. A carbon fiber-reinforced plastic (CFRP) incorporating this system is twice higher in after-shock compression strength than a CFRP incorporating a cyanate ester. The system withstands high temperatures, retaining at 200degC approximately 90% of the elastic modulus it exhibits at room temperature. 15 refs., 16 figs.

Intrinsic Tunneling in Phase Separated Manganites

Science.gov (United States)

Singh-Bhalla, G.; Selcuk, S.; Dhakal, T.; Biswas, A.; Hebard, A. F.

2009-02-01

We present evidence of direct electron tunneling across intrinsic insulating regions in submicrometer wide bridges of the phase-separated ferromagnet (La,Pr,Ca)MnO3. Upon cooling below the Curie temperature, a predominantly ferromagnetic supercooled state persists where tunneling across the intrinsic tunnel barriers (ITBs) results in metastable, temperature-independent, high-resistance plateaus over a large range of temperatures. Upon application of a magnetic field, our data reveal that the ITBs are extinguished resulting in sharp, colossal, low-field resistance drops. Our results compare well to theoretical predictions of magnetic domain walls coinciding with the intrinsic insulating phase.

A reactor/separator device for use in automated solid phase immunoassay

International Nuclear Information System (INIS)

Farina, P.R.; Ordonez, K.P.; Siewers, I.J.

1979-01-01

A reactor/separator device is described for use in automated solid phase immunoassay, including radioimmunoassays. The device is a column fitted at the bottom portion with a water impermeable disc which can hold, for example, immunoabsorbents, immobilized antisera or ion exchange resins. When the contents of the column supported by the disc are brought into contact with an aqueous phase containing reagents or reactants, a chemical reaction is initiated. After the reaction, centrifugally applied pressure forces the aqueous phase through the filter disc making it water permeable and separating a desired component for subsequent analysis. The reactor/separator device of the present invention permits kinetic solid phase assays (non-equilibrium conditions) to be carried out which would be difficult to perform by other conventional methods. (author)

Separation of piracetam derivatives on polysaccharide-based chiral stationary phases.

Science.gov (United States)

Kažoka, H; Koliškina, O; Veinberg, G; Vorona, M

2013-03-15

High-performance liquid chromatography was used for the enantiomeric separation of two chiral piracetam derivatives. The suitability of six commercially available polysaccharide-based chiral stationary phases (CSPs) under normal phase mode for direct enantioseparation has been investigated. The influence of the CSPs as well the nature and content of an alcoholic modifier in the mobile phase on separation and elution order was studied. It was established that CSP Lux Amylose-2 shows high chiral recognition ability towards 4-phenylsubstituted piracetam derivatives. Copyright © 2013 Elsevier B.V. All rights reserved.

Electric field tuning of phase separation in manganite thin films

KAUST Repository

Lourembam, James; Wu, Jianchun; Ding, Junfeng; Lin, Weinan; Wu, Tao

2014-01-01

In this paper, we investigate the electric field effect on epitaxial Pr0.65(Ca0.75Sr0.25)0.35MnO3 thin films in electric double-layer transistors. Different from the conventional transistors with semiconducting channels, the sub(micrometer)-scale phase separation in the manganite channels is expected to result in inhomogeneous distribution of mobile carriers and local enhancement of electric field. The field effect is much larger in the low-temperature phase separation region compared to that in the high-temperature polaron transport region. Further enhancement of electroresistance is achieved by applying a magnetic field, and a 250% modulation of resistance is observed at 80 K, equivalent to an increase of the ferromagnetic metallic phase fraction by 0.51%, as estimated by the general effective medium model. Our results illustrate the complementary nature of electric and magnetic field effects in phase-separated manganites, providing insights on such novel electronic devices based on complex oxides.

Electric field tuning of phase separation in manganite thin films

KAUST Repository

Lourembam, James

2014-01-29

In this paper, we investigate the electric field effect on epitaxial Pr0.65(Ca0.75Sr0.25)0.35MnO3 thin films in electric double-layer transistors. Different from the conventional transistors with semiconducting channels, the sub(micrometer)-scale phase separation in the manganite channels is expected to result in inhomogeneous distribution of mobile carriers and local enhancement of electric field. The field effect is much larger in the low-temperature phase separation region compared to that in the high-temperature polaron transport region. Further enhancement of electroresistance is achieved by applying a magnetic field, and a 250% modulation of resistance is observed at 80 K, equivalent to an increase of the ferromagnetic metallic phase fraction by 0.51%, as estimated by the general effective medium model. Our results illustrate the complementary nature of electric and magnetic field effects in phase-separated manganites, providing insights on such novel electronic devices based on complex oxides.

Phase separation in a gravity field

Czech Academy of Sciences Publication Activity Database

Krejčí, Pavel; Rocca, E.; Sprekels, J.

2011-01-01

Roč. 4, č. 2 (2011), s. 391-407 ISSN 1937-1632 R&D Projects: GA ČR GAP201/10/2315 Institutional research plan: CEZ:AV0Z10190503 Keywords : phase separation * existence and uniqueness * long-time behavior of solutions Subject RIV: BA - General Mathematics http://www.aimsciences.org/journals/displayArticles.jsp?paperID=5633

Effect of MoO3 addition on phase separation in borosilicate glasses

International Nuclear Information System (INIS)

Wakabayashi, Hajimu; Yamanaka, Hiroshi; Terai, Ryohei; Fukumoto, Shinji.

1987-01-01

The effect of MoO 3 addition on the phase separation of sodium borosilicate glasses has been studied by electron microscopic observation and electrical conductivity measurement. With increasing MoO 3 addition, the immiscibility temperatures rose, the growth rate of phase separation increased, and the immiscibility region in the Na 2 O-B 2 O 3 -SiO 2 system extended. When MoO 3 more than 5 mol% was added to the glasses, two stages of phase separation appeared ; one is metastable immiscibility, which takes place below the liquidus temperature, and the other is stable immiscibility, occurring above the liquidus temperature. The present experiment confirmed that the conductivity measurement of molten glasses is usefull to detect phase separation in the glasses, giving some suggestions for preventing the separation of molybdates in nuclear waste glasses and also for controlling the micro-pore sizes of porous glasses. (author)

Mixed-mode reversed phase/positively charged repulsion chromatography for intact protein separation.

Science.gov (United States)

Ding, Ling; Guo, Zhimou; Hu, Zhuo; Liang, Xinmiao

2017-05-10

A mixed-mode reversed phase/positively charged repulsion stationary phase C8PN composed of octyl and amino group has been developed for separation of intact protein. Before the separation of proteins, a set of probe compounds were employed to evaluate the chromatographic properties of C8PN, demonstrating typical reversed phase/positively charged repulsion interaction on this stationary phase as estimated. Then the new C8PN stationary phase was used to separate a standard protein mixture on the reversed phase mode. Compared with a commercial C4 stationary phase, it showed different selectivity for some proteins. In order to better understand the properties of C8PN, the effect of acetonitrile content was investigated based on retention equation. Higher values of the equation parameters on C8PN demonstrated that the protein retentions were more sensitive to the change of acetonitrile content. Besides, the influences of buffer salt additives on the protein retentions were also studied. The retention factors of the proteins got larger with the increase of buffer salt concentration, which confirmed the positively charged repulsion interaction on the column. Finally, the C8PN was further applied to separate oxidized- and reduced- forms of Recombinant Human Growth Hormone. Our study indicated the advantages and application potential of mixed-mode reversed phase/positively charged repulsion stationary phase for intact protein separation. Copyright © 2017 Elsevier B.V. All rights reserved.

Laser-induced separation of hydrogen isotopes in the liquid phase

International Nuclear Information System (INIS)

Beattie, W.; Freund, S.; Holland, R.; Maier, W.

1980-01-01

A process for separating hydrogen isotopes which comprises (A) forming a liquid phase of hydrogen-bearing feedstock compound at a temperature at which the spectral features of the feedstock compound are narrow enough or the absorption edges sharp enough to permit spectral features corresponding to the different hydrogen isotopes to be separated to be distinguished, (B) irradiating the liquid phase at said temperature with monochromatic radiation of a first wavelength which selectively or at least preferentially excites those molecules of said feedstock compound containing a first hydrogen isotope, and (C) subjecting the excited molecules to physical or chemical processes or a combination thereof whereby said first hydrogen isotope contained in said excited molecules is separated from other hydrogen isotopes contained in the unexcited molecules in said liquid phase

Film thickness dependence of phase separation and dewetting behaviors in PMMA/SAN blend films.

Science.gov (United States)

You, Jichun; Liao, Yonggui; Men, Yongfeng; Shi, Tongfei; An, Lijia

2010-09-21

Film thickness dependence of complex behaviors coupled by phase separation and dewetting in blend [poly(methyl methacrylate) (PMMA) and poly(styrene-ran-acrylonitrile) (SAN)] films on silicon oxide substrate at 175 °C was investigated by grazing incidence ultrasmall-angle X-ray scattering (GIUSAX) and in situ atomic force microscopy (AFM). It was found that the dewetting pathway was under the control of the parameter U(q0)/E, which described the initial amplitude of the surface undulation and original thickness of film, respectively. Furthermore, our results showed that interplay between phase separation and dewetting depended crucially on film thickness. Three mechanisms including dewetting-phase separation/wetting, dewetting/wetting-phase separation, and phase separation/wetting-pseudodewetting were discussed in detail. In conclusion, it is relative rates of phase separation and dewetting that dominate the interplay between them.

Particle separation by phase modulated surface acoustic waves.

Science.gov (United States)

Simon, Gergely; Andrade, Marco A B; Reboud, Julien; Marques-Hueso, Jose; Desmulliez, Marc P Y; Cooper, Jonathan M; Riehle, Mathis O; Bernassau, Anne L

2017-09-01

High efficiency isolation of cells or particles from a heterogeneous mixture is a critical processing step in lab-on-a-chip devices. Acoustic techniques offer contactless and label-free manipulation, preserve viability of biological cells, and provide versatility as the applied electrical signal can be adapted to various scenarios. Conventional acoustic separation methods use time-of-flight and achieve separation up to distances of quarter wavelength with limited separation power due to slow gradients in the force. The method proposed here allows separation by half of the wavelength and can be extended by repeating the modulation pattern and can ensure maximum force acting on the particles. In this work, we propose an optimised phase modulation scheme for particle separation in a surface acoustic wave microfluidic device. An expression for the acoustic radiation force arising from the interaction between acoustic waves in the fluid was derived. We demonstrated, for the first time, that the expression of the acoustic radiation force differs in surface acoustic wave and bulk devices, due to the presence of a geometric scaling factor. Two phase modulation schemes are investigated theoretically and experimentally. Theoretical findings were experimentally validated for different mixtures of polystyrene particles confirming that the method offers high selectivity. A Monte-Carlo simulation enabled us to assess performance in real situations, including the effects of particle size variation and non-uniform acoustic field on sorting efficiency and purity, validating the ability to separate particles with high purity and high resolution.

Hydration-Induced Phase Separation in Amphiphilic Polymer Matrices and its Influence on Voclosporin Release

Energy Technology Data Exchange (ETDEWEB)

Khan, I. John [The State Univ. of New Jersey, Piscataway, NJ (United States); Murthy, N. Sanjeeva [The State Univ. of New Jersey, Piscataway, NJ (United States); Kohn, Joachim [The State Univ. of New Jersey, Piscataway, NJ (United States)

2015-10-30

Voclosporin is a highly potent, new cyclosporine -- a derivative that is currently in Phase 3 clinical trials in the USA as a potential treatment for inflammatory diseases of the eye. Voclosporin represents a number of very sparingly soluble drugs that are difficult to administer. It was selected as a model drug that is dispersed within amphiphilic polymer matrices, and investigated the changing morphology of the matrices using neutron and x-ray scattering during voclosporin release and polymer resorption. The hydrophobic segments of the amphiphilic polymer chain are comprised of desaminotyrosyl-tyrosine ethyl ester (DTE) and desaminotyrosyl-tyrosine (DT), and the hydrophilic component is poly(ethylene glycol) (PEG). Water uptake in these matrices resulted in the phase separation of hydrophobic and hydrophilic domains that are a few hundred Angstroms apart. These water-driven morphological changes influenced the release profile of voclosporin and facilitated a burst-free release from the polymer. No such morphological reorganization was observed in poly(lactide-co-glycolide) (PLGA), which exhibits an extended lag period, followed by a burst-like release of voclosporin when the polymer was degraded. An understanding of the effect of polymer composition on the hydration behavior is central to understanding and controlling the phase behavior and resorption characteristics of the matrix for achieving long-term controlled release of hydrophobic drugs such as voclosporin.

Hydration-Induced Phase Separation in Amphiphilic Polymer Matrices and its Influence on Voclosporin Release

Directory of Open Access Journals (Sweden)

Joachim Kohn

2012-10-01

Full Text Available Voclosporin is a highly potent, new cyclosporine-A derivative that is currently in Phase 3 clinical trials in the USA as a potential treatment for inflammatory diseases of the eye. Voclosporin represents a number of very sparingly soluble drugs that are difficult to administer. We therefore selected it as a model drug that is dispersed within amphiphilic polymer matrices, and investigated the changing morphology of the matrices using neutron and x-ray scattering during voclosporin release and polymer resorption. The hydrophobic segments of the amphiphilic polymer chain are comprised of desaminotyrosyl-tyrosine ethyl ester (DTE and desaminotyrosyl-tyrosine (DT, and the hydrophilic component is poly(ethylene glycol (PEG. Water uptake in these matrices resulted in the phase separation of hydrophobic and hydrophilic domains that are a few hundred Angstroms apart. These water-driven morphological changes influenced the release profile of voclosporin and facilitated a burst-free release from the polymer. No such morphological reorganization was observed in poly(lactide-co-glycolide (PLGA, which exhibits an extended lag period, followed by a burst-like release of voclosporin when the polymer was degraded. An understanding of the effect of polymer composition on the hydration behavior is central to understanding and controlling the phase behavior and resorption characteristics of the matrix for achieving long-term controlled release of hydrophobic drugs such as voclosporin.

On the solubility of yttrium in RuO2

International Nuclear Information System (INIS)

Music, Denis; Zumdick, Naemi A.; Hallstedt, Bengt; Schneider, Jochen M.

2011-01-01

We have investigated the solubility of Y in rutile RuO 2 using experimental and theoretical methods. Nanostructured Ru-Y-O thin films were synthesized via combinatorial reactive sputtering with an O/metal ratio of 2.6 and a Y content of 0.3 to 12.6 at. %. A solubility limit of 1.7 at. % was identified using x-ray photoelectron spectroscopy and x-ray diffraction. Based on ab initio and thermodynamic modeling, the solubility of Y can be understood. Smaller Y amounts are incorporated into the lattice, forming a metastable film, with local structural deformations due to size effects. As the Y content is increased, extensive local structural deformations are observed, but phase separation does not occur due to kinetic limitations. Nanostructured RuO 2 alloyed with Y might lead to enhanced phonon scattering and quantum confinement effects, which in turn improve the thermoelectric efficiency.

Rapid Separation of Copper Phase and Iron-Rich Phase From Copper Slag at Low Temperature in a Super-Gravity Field

Science.gov (United States)

Lan, Xi; Gao, Jintao; Huang, Zili; Guo, Zhancheng

2018-06-01

A novel approach for quickly separating a metal copper phase and iron-rich phase from copper slag at low temperature is proposed based on a super-gravity method. The morphology and mineral evolution of the copper slag with increasing temperature were studied using in situ high-temperature confocal laser scanning microscopy and ex situ scanning electron microscopy and X-ray diffraction methods. Fe3O4 particles dispersed among the copper slag were transformed into FeO by adding an appropriate amount of carbon as a reducing agent, forming the slag melt with SiO2 at low temperature and assisting separation of the copper phase from the slag. Consequently, in a super-gravity field, the metallic copper and copper matte were concentrated as the copper phase along the super-gravity direction, whereas the iron-rich slag migrated in the opposite direction and was quickly separated from the copper phase. Increasing the gravity coefficient (G) significantly enhanced the separation efficiency. After super-gravity separation at G = 1000 and 1473 K (1200 °C) for 3 minutes, the mass fraction of Cu in the separated copper phase reached 86.11 wt pct, while that in the separated iron-rich phase was reduced to 0.105 wt pct. The recovery ratio of Cu in the copper phase was as high as up to 97.47 pct.

Thermodynamic evaluation of Cu-H-O-S-P system - Phase stabilities and solubilities for OFP-copper

International Nuclear Information System (INIS)

Magnusson, Hans; Frisk, Karin

2013-04-01

A thermodynamic evaluation for Cu-H-O-S-P has been made, with special focus on the phase stabilities and solubilities for OFP-copper. All binary systems including copper have been reviewed. Gaseous species and stoichiometric crystalline phases have been included for higher systems. Sulphur in OFP-copper will be found in sulphides. The sulphide can take different morphologies but constant stoichiometry Cu 2 S. The solubility of sulphur in FCC-copper reaches ppm levels already at 550 deg C and decreases with lower temperature. No phosphorus-sulphide will be stable, although the copper sulphide can be replaced by copper sulphates at high partial pressure oxygen like in the oxide scale. Phosphorus has a high affinity to oxygen, and phosphorus oxide P 4 O 10 and copper phosphates (Cu 2 P 2 O 7 and Cu 3 (PO 4 ) 2 ) are all more stable than copper oxide Cu 2 O. With hydrogen present at atmospheric pressure, copper phosphates Cu 2 P 2 O 7 and Cu 3 (P 2 O 6 OH) 2 are both more stable than water vapour or aqueous water at temperatures below 400 deg C. At high pressure conditions, the copper phosphates can be reduced giving water. However, the phosphates are still more stable than water vapour. The solubility limit of phosphorus in FCC-copper at 25 deg C is 510 ppm, in equilibrium with copper phosphide Cu 3 P. The major part of phosphorus in OFP-copper will be in solid solution. Oxygen in FCC-copper has a very low solubility. In the presence of a strong oxide forming element such as phosphorus in OFP-copper, the solubility decreases even more. Copper oxides will become stable first when all phosphorus has been consumed, which takes place at twice the phosphorus content, calculated in weight. Hydrogen has a low solubility in copper, calculated as 0.1 ppm at 675 deg C. No crystalline hydrogen phase has been found stable at atmospheric pressures and above 400 deg C. At lower temperatures the hydrogen containing phosphate Cu 3 (P 2 O 6 OH) 2 can become stable. Measured hydrogen

Polyoxyethylene/styrene - a model system for studying reaction-induced phase separation (RIPS)

International Nuclear Information System (INIS)

Sutton, D.; Stanford, J.L.; Ryan, A.J.

2003-01-01

Full text: Reaction-induced, phase-separation has been studied in polymer blends. A model crystalline-amorphous system consisted of semi-crystalline polyoxyethylene (POE) dissolved in the monomer styrene, which was employed as a reactive solvent to ease processing. When the styrene was polymerised to polystyrene (PS) in the mould, phase-separation and phase-inversion are induced, and a polymer blend was formed. POE was selected with a molar mass, Mn = 8578 g mol -1 and a polydispersity of 1.19 as determined using GPC. The polymerisation of styrene was initiated using 1 wt-% benzoin methyl ether (BME) and 0.2 wt-% 2,2'-azobisisobutyronitrile (AIBN) under ultra-violet (UV) light. The polymerisation kinetics were determined by monitoring the reduction in the intensity of the C=C stretching vibration band at 1631 cm -1 in the Raman spectrum of styrene. The onset times for the liquid-solid (L-S) phase-separation and crystallisation of POE from styrene/PS were observed using simultaneous small-angle X-ray scattering (SAXS) and wide-angle X-ray scattering (WAXS). Onset times for L-S phase-separation determined from the SAXS data were combined with the styrene polymerisation kinetics to plot the L-S phase-separation data onto a ternary phase diagram for the reactive system POE/styrene/PS at 45 and 50 deg C

Pressurized capillary electrochromatographic analysis of water-soluble vitamins by combining with on-line concentration technique.

Science.gov (United States)

Jia, Li; Liu, Yaling; Du, Yanyan; Xing, Da

2007-06-22

A pressurized capillary electrochromatography (pCEC) system was developed for the separation of water-soluble vitamins, in which UV absorbance was used as the detection method and a monolithic silica-ODS column as the separation column. The parameters (type and content of organic solvent in the mobile phase, type and concentration of electrolyte, pH of the electrolyte buffer, applied voltage and flow rate) affecting the separation resolution were evaluated. The combination of two on-line concentration techniques, namely, solvent gradient zone sharpening effect and field-enhanced sample stacking, was utilized to improve detection sensitivity, which proved to be beneficial to enhance the detection sensitivity by enabling the injection of large volumes of samples. Coupling electrokinetic injection with the on-line concentration techniques was much more beneficial for the concentration of positively charged vitamins. Comparing with the conventional injection mode, the enhancement in the detection sensitivities of water-soluble vitamins using the on-line concentration technique is in the range of 3 to 35-fold. The developed pCEC method was applied to evaluate water-soluble vitamins in corns.

Effect of temperature gradient on liquid-liquid phase separation in a polyolefin blend.

Science.gov (United States)

Jiang, Hua; Dou, Nannan; Fan, Guoqiang; Yang, Zhaohui; Zhang, Xiaohua

2013-09-28

We have investigated experimentally the structure formation processes during phase separation via spinodal decomposition above and below the spinodal line in a binary polymer blend system exposed to in-plane stationary thermal gradients using phase contrast optical microscopy and temperature gradient hot stage. Below the spinodal line there is a coupling of concentration fluctuations and thermal gradient imposed by the temperature gradient hot stage. Also under the thermal gradient annealing phase-separated domains grow faster compared with the system under homogeneous temperature annealing on a zero-gradient or a conventional hot stage. We suggest that the in-plane thermal gradient accelerates phase separation through the enhancement in concentration fluctuations in the early and intermediate stages of spinodal decomposition. In a thermal gradient field, the strength of concentration fluctuation close to the critical point (above the spinodal line) is strong enough to induce phase separation even in one-phase regime of the phase diagram. In the presence of a temperature gradient the equilibrium phase diagrams are no longer valid, and the systems with an upper critical solution temperature can be quenched into phase separation by applying the stationary temperature gradient. The in-plane temperature gradient drives enhanced concentration fluctuations in a binary polymer blend system above and below the spinodal line.

Distribution of six radionuclides between soluble and particulate phase at the sea-freshwater interface

International Nuclear Information System (INIS)

Peres, J.M.

1984-01-01

The distribution of the soluble and particulate phases of radionuclides has been studied in water samples of various salinities (0 per mill; 3.8 per mill; 7.6 per mill; 15.2 per mill; 22.8 per mill; 30.4 per mill; 34 per mill). Cesium 137, cobalt 60, manganese 54, zinc 65, chromium 51 and sodium 22 were investigated. The results are expressed as retention percentages or distribution coefficients (Kd). Increased salinities resulted in decreased retention rates varying with the radionuclides; this appeared with the lowest salinities, and the evolution was small beyond 7 per mill. Other parameters were considered beside salinity, viz.: the suspended matter characteristics (mineralogy, particle size distribution); particulate load of water; organic content, whether associated to the soluble or particulate phase; physico-chemical forms of the radionuclides. To determine the particle size spectra of the suspended matter in the experimental samples, a laser granulometer was used [fr

Separation of multiphosphorylated peptide isomers by hydrophilic interaction chromatography on an aminopropyl phase.

Science.gov (United States)

Singer, David; Kuhlmann, Julia; Muschket, Matthias; Hoffmann, Ralf

2010-08-01

The separation of isomeric phosphorylated peptides is challenging and often impossible for multiphosphorylated isomers using chromatographic and capillary electrophoretic methods. In this study we investigated the separation of a set of single-, double-, and triple-phosphorylated peptides (corresponding to the human tau protein) by ion-pair reversed-phase chromatography (IP-RPC) and hydrophilic interaction chromatography (HILIC). In HILIC both hydroxyl and aminopropyl stationary phases were tested with aqueous acetonitrile in order to assess their separation efficiency. The hydroxyl phase separated the phosphopeptides very well from the unphosphorylated analogue, while on the aminopropyl phase even isomeric phosphopeptides attained baseline separation. Thus, up to seven phosphorylated versions of a given tau domain were separated. Furthermore, the low concentration of an acidic ammonium formate buffer allowed an online analysis with electrospray ionization tandem mass spectrometry (ESI-MS/MS) to be conducted, enabling peptide sequencing and identification of phosphorylation sites.

Quantitative analysis of aqueous phase composition of model dentin adhesives experiencing phase separation

Science.gov (United States)

Ye, Qiang; Park, Jonggu; Parthasarathy, Ranganathan; Pamatmat, Francis; Misra, Anil; Laurence, Jennifer S.; Marangos, Orestes; Spencer, Paulette

2013-01-01

There have been reports of the sensitivity of our current dentin adhesives to excess moisture, for example, water-blisters in adhesives placed on over-wet surfaces, and phase separation with concomitant limited infiltration of the critical dimethacrylate component into the demineralized dentin matrix. To determine quantitatively the hydrophobic/hydrophilic components in the aqueous phase when exposed to over-wet environments, model adhesives were mixed with 16, 33, and 50 wt % water to yield well-separated phases. Based upon high-performance liquid chromatography coupled with photodiode array detection, it was found that the amounts of hydrophobic BisGMA and hydrophobic initiators are less than 0.1 wt % in the aqueous phase. The amount of these compounds decreased with an increase in the initial water content. The major components of the aqueous phase were hydroxyethyl methacrylate (HEMA) and water, and the HEMA content ranged from 18.3 to 14.7 wt %. Different BisGMA homologues and the relative content of these homologues in the aqueous phase have been identified; however, the amount of crosslinkable BisGMA was minimal and, thus, could not help in the formation of a crosslinked polymer network in the aqueous phase. Without the protection afforded by a strong crosslinked network, the poorly photoreactive compounds of this aqueous phase could be leached easily. These results suggest that adhesive formulations should be designed to include hydrophilic multimethacrylate monomers and water compatible initiators. PMID:22331596

Studies on Three Liquid Phase Extraction (TLPE) system for separation of rare earths

International Nuclear Information System (INIS)

Yadav, Kartikey K.; Singh, D.K.; Anitha, M.; Singh, H.

2014-01-01

Three-liquid-phase extraction (TLPE) is relatively a new separation technique, which takes the advantage of the differences in physicochemical properties of three coexisted phases to achieve multi-phase liquid separation of two or more components in one-step extraction. TLPE system consists of three liquid layers namely an organic solvent phase (organophosphorous type) and two aqueous phases one rich in polymer phase (poly alkylene glycol) and other a salt solution. To study the feasibility of using such system for separation of rare earths, it is important to optimize the preparatory conditions by selective suitable polymer and salt solutions at an appropriate pH to obtain a stable three phase layers to effect the separation. D2EHPA (di-2-ethyl hexyl phosphoric acid) is a well- established extractant in the rare earth industry and has been chosen in the present work to form a TLPE with polymer and salt solution. In the present investigation after preparing the stable three phase, the feasibility of using TLPE has been examined to separate rare earths from a multicomponent solutions. This study has demonstrated the ability of TLPE having D2EHPA as organic phase to separate rare earths from a multicomponent system. Effect of pH, concentration and types of polymer, complexing agent and D2EHPA concentration has been studied. Variation in pH study indicated that 4.0 leads to extraction of rare earths in the polymer phase. PEG 600 was found to be best amongst the polymer investigated. Presence of DTPA as complexing agent in the salt solution having pH >4.0 resulted in enhanced extraction of rare earths in PEG phase

On the phase form of a deformation quantization with separation of variables

OpenAIRE

Karabegov, Alexander

2015-01-01

Given a star product with separation of variables on a pseudo-Kaehler manifold, we obtain a new formal (1,1)-form from its classifying form and call it the phase form of the star product. The cohomology class of a star product with separation of variables equals the class of its phase form. We show that the phase forms can be arbitrary and they bijectively parametrize the star products with separation of variables. We also describe the action of a change of the formal parameter on a star prod...

Phase separation of comb polymer nanocomposite melts.

Science.gov (United States)

Xu, Qinzhi; Feng, Yancong; Chen, Lan

2016-02-07

In this work, the spinodal phase demixing of branched comb polymer nanocomposite (PNC) melts is systematically investigated using the polymer reference interaction site model (PRISM) theory. To verify the reliability of the present method in characterizing the phase behavior of comb PNCs, the intermolecular correlation functions of the system for nonzero particle volume fractions are compared with our molecular dynamics simulation data. After verifying the model and discussing the structure of the comb PNCs in the dilute nanoparticle limit, the interference among the side chain number, side chain length, nanoparticle-monomer size ratio and attractive interactions between the comb polymer and nanoparticles in spinodal demixing curves is analyzed and discussed in detail. The results predict two kinds of distinct phase separation behaviors. One is called classic fluid phase boundary, which is mediated by the entropic depletion attraction and contact aggregation of nanoparticles at relatively low nanoparticle-monomer attraction strength. The second demixing transition occurs at relatively high attraction strength and involves the formation of an equilibrium physical network phase with local bridging of nanoparticles. The phase boundaries are found to be sensitive to the side chain number, side chain length, nanoparticle-monomer size ratio and attractive interactions. As the side chain length is fixed, the side chain number has a large effect on the phase behavior of comb PNCs; with increasing side chain number, the miscibility window first widens and then shrinks. When the side chain number is lower than a threshold value, the phase boundaries undergo a process from enlarging the miscibility window to narrowing as side chain length increases. Once the side chain number overtakes this threshold value, the phase boundary shifts towards less miscibility. With increasing nanoparticle-monomer size ratio, a crossover of particle size occurs, above which the phase separation

Hydration and phase separation of polyethylene glycol in copolymers of tyrosine derived carbonates.

Science.gov (United States)

Sanjeeva Murthy, N.; Wang, Wenjie; Kohn, Joachim

2009-03-01

Effect of PEG fraction and its block size on the temperature-induced phase transitions and the hydration-induced phase separation were investigated in a copolymer of desaminotyrosyl tyrosine ethyl ester (DTE) and PEG using simultaneous SAXS/WAXS/DSC. The PEG segments crystallized when the block size was at least 2000 Daltons and present at ˜ 40 wt%, and raised the Tg of the polymer by ˜ 15 ^oC. The PEG blocks in dry polymers with up to 50 wt% PEG, even when crystalline, were found to be uniformly distributed with no evidence of phase separation at 10 nm length scales. The non-iodinated PEG-rich sample with 30 mole% PEG2k showed the lower critical solution temperature (LCST) behavior with PEG blocks forming a separate phase above -21 ^oC. In the iodinated version of this polymer, the PEG2k blocks were phase separated in the solid phase. In all samples, whether PEG was crystalline or not, hydration induced PEG to separate into 15 nm hydrated domains. Phase behavior was dependent on whether poly(DTE) or the PEG was the major (matrix) phase. Changes in the mobility of the chains brought about by water-mediated hydrogen-bonding, and modulated by heat, appear to be the common underlying explanation for the range of observed phase behavior.

Phase separation and structure formation in gadolinium based liquid and glassy metallic alloys

International Nuclear Information System (INIS)

Han, Junhee

2014-01-01

In this PhD research the liquid-liquid phase separation phenomena in Gd-based alloys was investigated in terms of phase equilibria, microstructure formation upon quenching the melt and corresponding magnetic properties of phase-separated metallic glasses. The phase diagrams of the binary subsystems Gd-Zr and Gd-Ti were experimentally reassessed. Especially the phase equilibria with the liquid phase could be determined directly by combining in situ high energy synchrotron X-ray diffraction with electrostatic levitation of the melt. The Gd-Zr system is of eutectic type with a metastable miscibility gap. The eutectic composition at 18 ± 2 at.% Zr, the liquidus line and the coexistence of bcc-Zr and bcc-Gd at elevated temperature could be determined. The Gd-Ti system is a monotectic system. The experimental observations in this work led to improved new Gd-Zr and Gd-Ti phase diagrams. The phase equilibria of the ternary Gd-Ti-Co system were analyzed for two alloy compositions. The XRD patterns for molten Gd 35 Ti 35 Co 30 gave direct evidence for the coexistence of two liquid phases formed by liquid-liquid phase separation. The first experimental and thermodynamic assessment of the ternary Gd-Ti-Co system revealed that the stable miscibility gap of binary Gd-Ti extends into the ternary Gd-Ti-Co system (up to about 30 at.% Co). New phase-separated metallic glasses were synthesized in Gd-TM-Co-Al (TM = Hf, Ti or Zr) alloys. The microstructure was characterized in terms of composition and cooling rate dependence of phase separation. Due to large positive enthalpy of mixing between Gd on the one side and Hf, Ti or Zr on the other side, the alloys undergo liquid-liquid phase separation during rapid quenching the melt. The parameters determining the microstructure development during phase separation are the thermodynamic properties of the liquid phase, kinetic parameters and quenching conditions. By controlling these parameters and conditions the microstructure can be

Detection of various phases in liquids from the hypersound velocity and damping near closed phase-separation regions of solutions

International Nuclear Information System (INIS)

Kovalenko, K. V.; Krivokhizha, S. V.; Chaban, I. A.; Chaikov, L. L.

2008-01-01

Theoretical analysis revealed that experimental results obtained in our studies on hypersound propagation in a guaiacol-glycerol solution in the vicinity of the closed phase-separation region, double critical point, and special point, as well as the origin of these regions, can be explained by the presence of two different phases (I and II) of the solution with phase-transition temperature T 0 . Temperature T 0 coincides with the temperature at the center of closed phase-separation regions, as well as with the double critical point and with the special point. In (Frenkel) phase I, molecules are in potential wells whose depth exceeds the thermal energy of a molecule, while thermal energy in (gaslike) phase II is higher than the potential well depth. At the lower critical point, the thermodynamic potential of phase I is equal to the thermodynamic potential of the phase-separated solution. At the upper critical point, the thermodynamic potential of phase II is equal to the thermodynamic potential of the phase-separated solution. The observed broad dome of the hypersound absorption coefficient near T 0 can be explained by the contribution associated with fluctuations of the order parameter corresponding to the transition from phase I to phase II. The difference in the temperature coefficients of hypersound velocity on different sides of T 0 and some other effects are also explained

On the solubility of yttrium in RuO{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Music, Denis; Zumdick, Naemi A.; Hallstedt, Bengt; Schneider, Jochen M. [Materials Chemistry, RWTH Aachen University, D-52056 Aachen (Germany)

2011-09-01

We have investigated the solubility of Y in rutile RuO{sub 2} using experimental and theoretical methods. Nanostructured Ru-Y-O thin films were synthesized via combinatorial reactive sputtering with an O/metal ratio of 2.6 and a Y content of 0.3 to 12.6 at. %. A solubility limit of 1.7 at. % was identified using x-ray photoelectron spectroscopy and x-ray diffraction. Based on ab initio and thermodynamic modeling, the solubility of Y can be understood. Smaller Y amounts are incorporated into the lattice, forming a metastable film, with local structural deformations due to size effects. As the Y content is increased, extensive local structural deformations are observed, but phase separation does not occur due to kinetic limitations. Nanostructured RuO{sub 2} alloyed with Y might lead to enhanced phonon scattering and quantum confinement effects, which in turn improve the thermoelectric efficiency.

Robust water fat separated dual-echo MRI by phase-sensitive reconstruction.

Science.gov (United States)

Romu, Thobias; Dahlström, Nils; Leinhard, Olof Dahlqvist; Borga, Magnus

2017-09-01

The purpose of this work was to develop and evaluate a robust water-fat separation method for T1-weighted symmetric two-point Dixon data. A method for water-fat separation by phase unwrapping of the opposite-phase images by phase-sensitive reconstruction (PSR) is introduced. PSR consists of three steps; (1), identification of clusters of tissue voxels; (2), unwrapping of the phase in each cluster by solving Poisson's equation; and (3), finding the correct sign of each unwrapped opposite-phase cluster, so that the water-fat images are assigned the correct identities. Robustness was evaluated by counting the number of water-fat swap artifacts in a total of 733 image volumes. The method was also compared to commercial software. In the water-fat separated image volumes, the PSR method failed to unwrap the phase of one cluster and misclassified 10. One swap was observed in areas affected by motion and was constricted to the affected area. Twenty swaps were observed surrounding susceptibility artifacts, none of which spread outside the artifact affected regions. The PSR method had fewer swaps when compared to commercial software. The PSR method can robustly produce water-fat separated whole-body images based on symmetric two-echo spoiled gradient echo images, under both ideal conditions and in the presence of common artifacts. Magn Reson Med 78:1208-1216, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

Scientific and engineering aspects of the Active Phase Separator

International Nuclear Information System (INIS)

Klipping, G.

1986-01-01

The development of the Active Phase Separator (APS), which was initiated by the rather extreme demands for the GIRL (German Infrared Laboratory) mission, is reviewed. As a final result the APS model V is presented, which is suitable for space qualification and can be considered not only as a universal phase separator but also as a multifunctional component for space cooling systems, allowing a simplification of the valve plan. Besides discussing the scientific results obtained with annular flow channels and presentation of performance tests with the APS, the status of the actual IR telescopes IRAS, (Infra Red Astronomy Sattelite), GIRL, and ISO (Infrared Space Observatory) is summarized

Thermodynamic evaluation of Cu-H-O-S-P system - Phase stabilities and solubilities for OFP-copper

Energy Technology Data Exchange (ETDEWEB)

Magnusson, Hans; Frisk, Karin [Swerea KIMAB, Kista (Sweden)

2013-04-15

A thermodynamic evaluation for Cu-H-O-S-P has been made, with special focus on the phase stabilities and solubilities for OFP-copper. All binary systems including copper have been reviewed. Gaseous species and stoichiometric crystalline phases have been included for higher systems. Sulphur in OFP-copper will be found in sulphides. The sulphide can take different morphologies but constant stoichiometry Cu{sub 2}S. The solubility of sulphur in FCC-copper reaches ppm levels already at 550 deg C and decreases with lower temperature. No phosphorus-sulphide will be stable, although the copper sulphide can be replaced by copper sulphates at high partial pressure oxygen like in the oxide scale. Phosphorus has a high affinity to oxygen, and phosphorus oxide P{sub 4}O{sub 10} and copper phosphates (Cu{sub 2}P{sub 2}O{sub 7} and Cu{sub 3}(PO{sub 4}){sub 2}) are all more stable than copper oxide Cu{sub 2}O. With hydrogen present at atmospheric pressure, copper phosphates Cu{sub 2}P{sub 2}O{sub 7} and Cu{sub 3}(P{sub 2}O{sub 6}OH){sub 2} are both more stable than water vapour or aqueous water at temperatures below 400 deg C. At high pressure conditions, the copper phosphates can be reduced giving water. However, the phosphates are still more stable than water vapour. The solubility limit of phosphorus in FCC-copper at 25 deg C is 510 ppm, in equilibrium with copper phosphide Cu{sub 3}P. The major part of phosphorus in OFP-copper will be in solid solution. Oxygen in FCC-copper has a very low solubility. In the presence of a strong oxide forming element such as phosphorus in OFP-copper, the solubility decreases even more. Copper oxides will become stable first when all phosphorus has been consumed, which takes place at twice the phosphorus content, calculated in weight. Hydrogen has a low solubility in copper, calculated as 0.1 ppm at 675 deg C. No crystalline hydrogen phase has been found stable at atmospheric pressures and above 400 deg C. At lower temperatures the hydrogen

Complexation-Induced Phase Separation: Preparation of Metal-Rich Polymeric Membranes

KAUST Repository

Villalobos, Luis Francisco

2017-01-01

The majority of state-of-the-art polymeric membranes for industrial or medical applications are fabricated by phase inversion. Complexation induced phase separation (CIPS)—a surprising variation of this well-known process—allows direct fabrication

Integral equation theory study on the phase separation in star polymer nanocomposite melts.

Science.gov (United States)

Zhao, Lei; Li, Yi-Gui; Zhong, Chongli

2007-10-21

The polymer reference interaction site model theory is used to investigate phase separation in star polymer nanocomposite melts. Two kinds of spinodal curves were obtained: classic fluid phase boundary for relatively low nanoparticle-monomer attraction strength and network phase boundary for relatively high nanoparticle-monomer attraction strength. The network phase boundaries are much more sensitive with nanoparticle-monomer attraction strength than the fluid phase boundaries. The interference among the arm number, arm length, and nanoparticle-monomer attraction strength was systematically investigated. When the arm lengths are short, the network phase boundary shows a marked shift toward less miscibility with increasing arm number. When the arm lengths are long enough, the network phase boundaries show opposite trends. There exists a crossover arm number value for star polymer nanocomposite melts, below which the network phase separation is consistent with that of chain polymer nanocomposite melts. However, the network phase separation shows qualitatively different behaviors when the arm number is larger than this value.

Separation of Chloroplast Pigments Using Reverse Phase Chromatography.

Science.gov (United States)

Reese, R. Neil

1997-01-01

Presents a protocol that uses reverse phase chromatography for the separation of chloroplast pigments. Provides a simple and relatively safe procedure for use in teaching laboratories. Discusses pigment extraction, chromatography, results, and advantages of the process. (JRH)

Molecular dynamics simulations of phase separation in the presence of surfactants

DEFF Research Database (Denmark)

Laradji, Mohamed; Mouritsen, Ole G.; Toxvaerd, Søren

1994-01-01

The dynamics of phase separation in two-dimensional binary mixtures diluted by surfactants is studied by means of molecular dynamics simulations. In contrast to pure binary systems, characterized by an algebraic time dependence of the average domain size, we find that systems containing surfactants...... not fully phase separate, we observe a dynamical scaling which is independent of the surfactant concentration. The results of these simulations are in general in agreement with previous Langevin simulations [Laradji, Guo, Grant, and Zuckermann, J. Phys. A 44, L629 (1991)] and a theory of Ostwald ripening...... exhibit nonalgebraic, slow dynamics. The average domain size eventually saturates at a value inversely proportional to the surfactant concentration. We also find that phase separation in systems with different surfactant concentrations follow a crossover scaling form. Finally, although these systems do...

Speciation and Oxidative Stability of Alkaline Soluble, Non-Pertechnetate Technetium

Energy Technology Data Exchange (ETDEWEB)

Levitskaia, Tatiana G. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Rapko, Brian M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Anderson, Amity [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Peterson, James M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Chatterjee, Sayandev [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Walter, Eric D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Cho, Herman M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Washton, Nancy M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

2014-09-30

The long half-life, complex chemical behavior in tank waste, limited incorporation in mid- to high-temperature immobilization processes, and high mobility in subsurface environments make technetium (Tc) one of the most difficult contaminants to dispose of and/or remediate. Technetium exists predominantly in the liquid tank waste phase as the relatively mobile form of pertechnetate, TcO₄^-. However, based on experimentation to date a significant fraction of the soluble Tc cannot be effectively separated from the wastes and may be present as a non- pertechnetate species. The presence of a non-pertechnetate species significantly complicates disposition of low-activity waste (LAW), and the development of methods to either convert them to pertechnetate or to separate directly is needed. The challenge is the uncertainty regarding the chemical form of the alkaline-soluble low-valent non-pertechnetate species in the liquid tank waste. This report summarizes work done in fiscal year (FY) 2014 exploring the chemistry of a low-valence technetium(I) species, [(CO)₃Tc(H₂O)₃]⁺, a compound of interest due to its implication in the speciation of alkaline-soluble technetium in several Hanford tank waste supernatants.

Amide-induced phase separation of hexafluoroisopropanol-water mixtures depending on the hydrophobicity of amides.

Science.gov (United States)

Takamuku, Toshiyuki; Wada, Hiroshi; Kawatoko, Chiemi; Shimomura, Takuya; Kanzaki, Ryo; Takeuchi, Munetaka

2012-06-21

Amide-induced phase separation of hexafluoro-2-propanol (HFIP)-water mixtures has been investigated to elucidate solvation properties of the mixtures by means of small-angle neutron scattering (SANS), (1)H and (13)C NMR, and molecular dynamics (MD) simulation. The amides included N-methylformamide (NMF), N-methylacetamide (NMA), and N-methylpropionamide (NMP). The phase diagrams of amide-HFIP-water ternary systems at 298 K showed that phase separation occurs in a closed-loop area of compositions as well as an N,N-dimethylformamide (DMF) system previously reported. The phase separation area becomes wider as the hydrophobicity of amides increases in the order of NMF amides due to the hydrophobic interaction gives rise to phase separation of the mixtures. In contrast, the disruption of HFIP clusters causes the recovery of the homogeneity of the ternary systems. The present results showed that HFIP clusters are evolved with increasing amide content to the lower phase separation concentration in the same mechanism among the four amide systems. However, the disruption of HFIP clusters in the NMP and DMF systems with further increasing amide content to the upper phase separation concentration occurs in a different way from those in the NMF and NMA systems.

Phase Separation in Doped Mott Insulators

Directory of Open Access Journals (Sweden)

Chuck-Hou Yee

2015-04-01

Full Text Available Motivated by the commonplace observation of Mott insulators away from integer filling, we construct a simple thermodynamic argument for phase separation in first-order doping-driven Mott transitions. We show how to compute the critical dopings required to drive the Mott transition using electronic structure calculations for the titanate family of perovskites, finding good agreement with experiment. The theory predicts that the transition is percolative and should exhibit Coulomb frustration.

Numerical simulation of gas-solid two-phase flow in U-beam separator

International Nuclear Information System (INIS)

Zhou, X Y; Chen, X P; Dou, H S; Zhang, H Z; Ruan, J M

2015-01-01

Numerical simulation is carried out for gas-solid two-phase flow in a U-beam separator. In this study, the U-beam is altered with the inlet fins in order to improve the performance of the separator. The inlet fin angle of the separator are 30°, 35°, 40°, 45°, 50°, 55 ° and 60°. The governing equations are the Reynolds-Averaged Navier-Stokes equation with the standard k-ε model and the discrete phase model (DPM) describing the discrete two - phase flow as well as stochastic tracking model. Results show that the pressure drop deviation with fins is within 3% from those without fins. It is found that there is a maximum separation efficiency at the fin angle of 35°. Fin induces generation of a stagnation region which could collect particles and lead to change of vortical structures. The fin induced flow also causes the turbulent intensity inside the baffle to decrease to facilitate separation

Vitrification and Crystallization of Phase-Separated Metallic Liquid

Directory of Open Access Journals (Sweden)

Yun Cheng

2017-02-01

Full Text Available The liquid–liquid phase separation (LLPS behavior of Fe50Cu50 melt from 3500 K to 300 K with different rapid quenching is investigated by molecular dynamics (MD simulation based on the embedded atom method (EAM. The liquid undergoes metastable phase separation by spinodal decomposition in the undercooled regime and subsequently solidifies into three different Fe-rich microstructures: the interconnected-type structure is kept in the glass and crystal at a higher cooling rate, while the Fe-rich droplets are found to crystalize at a lower cooling rate. During the crystallization process, only Fe-rich clusters can act as the solid nuclei. The twinning planes can be observed in the crystal and only the homogeneous atomic stacking shows mirror symmetry along the twinning boundary. Our present work provides atomic-scale understanding of LLPS melt during the cooling process.

Spectroscopy, modeling and computation of metal chelate solubility in supercritical CO2

International Nuclear Information System (INIS)

Brennecke, J.F.; Stadtherr, M.A.

1999-01-01

The overall objectives of this project were to gain a fundamental understanding of the solubility and phase behavior of metal chelates in supercritical CO 2 . Extraction with CO 2 is an excellent way to remove organic compounds from soils, sludges and aqueous solutions, and recent research has demonstrated that, together with chelating agents, it is a viable way to remove metals, as well. In this project the authors sought to gain fundamental knowledge that is vital to computing phase behavior, and modeling and designing processes using CO 2 to separate organics and metal compounds from DOE mixed wastes. The overall program was a comprehensive one to measure, model and compute the solubility of metal chelate complexes in supercritical CO 2 and CO 2 /cosolvent mixtures. Through a combination of phase behavior measurements, spectroscopy and the development of a new computational technique, the authors have achieved a completely reliable way to model metal chelate solubility in supercritical CO 2 and CO 2 /co-contaminant mixtures. Thus, they can now design and optimize processes to extract metals from solid matrices using supercritical CO 2 , as an alternative to hazardous organic solvents that create their own environmental problems, even while helping in metals decontamination

Solvent-mediated pathways to gelation and phase separation in suspensions of grafted nanoparticles

KAUST Repository

Anyfantakis, Manos

2009-01-01

We explore the role of the solvent medium on the interplay between gelation and phase separation in suspensions of organosilicate planar hybrids grafted with hydrocarbon chains. We establish their phase diagram by means of dynamic light scattering, rheology and visual observations, and different routes to gelation, depending on the solvent used. In agreement with earlier works, the solvent quality for the grafted chains at a given temperature controls the balance between attractions and repulsions, and hence the phase diagram of the nanoparticles and their tendency to gel. Here we show how to tune the suspension state and hence its rheology. For decane, a good solvent for the hydrocarbon chains, gelation occurs at rather low volume fractions in the presence of phase separation. This is due to the interdigitation of solvent molecules with the grafted chains, resulting in their crystalline packing that promotes the attraction between particles. For toluene, a solvent of reduced quality for the hydrocarbon chains, no interdigitation takes place, and hence gelation is triggered by clustering at higher volume fractions before phase separation. Our results support the generic picture of complex kinetic arrest/phase separation interplay in soft matter, where phase separation can proceed, be interrupted or be completely inhibited. A number of interesting possibilities for tailoring the rheology of grafted colloidal systems emerge. © 2009 The Royal Society of Chemistry.

Phase separation of cesium from lead borosilicate glass by heat treatment under a reducing atmosphere

Energy Technology Data Exchange (ETDEWEB)

Xu, Zhanglian; Okada, Takashi, E-mail: t-okada@u-fukui.ac.jp; Nishimura, Fumihiro; Yonezawa, Susumu

2016-11-05

Highlights: • Cesium was phase separated from lead borosilicate glass under a reductive atmosphere. • The phase separation occurred on the glass surface that was in contact with the gas. • The leachability of cesium was enhanced by the phase separation. • The degree of such enhancement varied depending on the heat treatment conditions. - Abstract: A phase-separation technique for removing sodium from glass using a heat-treatment method under a reducing atmosphere was previously developed for sodium recovery from waste glass. In this study, this technique was applied to cesium-containing lead borosilicate glass to concentrate the cesium in phase-separated sodium-rich materials for efficient cesium extraction. The theoretical phase-separation temperature of the sodium-rich phase was simulated by thermodynamic equilibrium calculations and was predicted to occur below 700 °C for lead borosilicate glass. Experimentally, a simulated lead borosilicate glass was melted at 1000 °C and subsequently annealed below 700 °C under a CO-containing reducing atmosphere. The phase separation of cesium was found to occur with sodium enrichment on the glass surface that was in contact with the gas phase, promoting cesium extraction from the treated glass using water. The cesium extraction efficiency was affected by the surface area of the treated glass that was in contact with water, and under the examined conditions, the cesium extraction efficiency was up to 66%. Phase separation using reductive heat treatment, combined with a water leaching technique, is suggested to be effective for extracting cesium incorporated in borosilicate glass waste.

Phase-Separated Polyaniline/Graphene Composite Electrodes for High-Rate Electrochemical Supercapacitors.

Science.gov (United States)

Wu, Jifeng; Zhang, Qin'e; Zhou, An'an; Huang, Zhifeng; Bai, Hua; Li, Lei

2016-12-01

Polyaniline/graphene hydrogel composites with a macroscopically phase-separated structure are prepared. The composites show high specific capacitance and excellent rate performance. Further investigation demonstrates that polyaniline inside the graphene hydrogel has low rate performance, thus a phase-separated structure, in which polyaniline is mainly outside the graphene hydrogel matrix, can enhance the rate performance of the composites. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Solid solubility, phase transitions, thermal expansion, and compressibility in Sc{sub 1−x}Al{sub x}F{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Morelock, Cody R.; Gallington, Leighanne C. [School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332-0400 (United States); Wilkinson, Angus P., E-mail: angus.wilkinson@chemistry.gatech.edu [School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332-0400 (United States); School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0245 (United States)

2015-02-15

With the goal of thermal expansion control, the synthesis and properties of Sc{sub 1−x}Al{sub x}F{sub 3} were investigated. The solubility limit of AlF{sub 3} in ScF{sub 3} at ∼1340 K is ∼50%. Solid solutions (x≤0.50) were characterized by synchrotron powder diffraction at ambient pressure between 100 and 900 K and at pressures <0.414 GPa while heating from 298 to 523 K. A phase transition from cubic to rhombohedral is observed. The transition temperature increases smoothly with Al{sup 3+} content, approaching 500 K at the solid solubility limit, and also upon compression at fixed Al{sup 3+} content. The slope of the pressure–temperature phase boundary is ∼0.5 K MPa{sup −1}, which is steep relative to that for most symmetry-lowering phase transitions in perovskites. The volume coefficient of thermal expansion (CTE) for the rhombohedral phase is strongly positive, but the cubic-phase CTE varies from negative (x<0.15) to near-zero (x=0.15) to positive (x>0.20) between ∼600 and 800 K. The cubic solid solutions elastically stiffen on heating, while Al{sup 3+} substitution causes softening at a given temperature. - Graphical abstract: The cubic-phase coefficient of thermal expansion for Sc{sub 1−x}Al{sub x}F{sub 3}(solubility limit ∼50% at ∼1340 K) becomes more positive with increased Al{sup 3+} substitution, but the average isothermal bulk modulus decreases (elastic softening). - Highlights: • The solubility limit of AlF{sub 3} in ScF{sub 3} at ∼1340 K is ∼50%. • The phase transition temperature of Sc{sub 1−x}Al{sub x}F{sub 3} increases smoothly with x. • The cubic-phase volume CTE varies from negative to positive with increasing x. • The cubic solid solutions elastically stiffen on heating. • Al{sup 3+} substitution causes softening at a given temperature.

Phase-Separated Liposomes Enhance the Efficiency of Macromolecular Delivery to the Cellular Cytoplasm.

Science.gov (United States)

Imam, Zachary I; Kenyon, Laura E; Ashby, Grant; Nagib, Fatema; Mendicino, Morgan; Zhao, Chi; Gadok, Avinash K; Stachowiak, Jeanne C

2017-10-01

From viruses to organelles, fusion of biological membranes is used by diverse biological systems to deliver macromolecules across membrane barriers. Membrane fusion is also a potentially efficient mechanism for the delivery of macromolecular therapeutics to the cellular cytoplasm. However, a key shortcoming of existing fusogenic liposomal systems is that they are inefficient, requiring a high concentration of fusion-promoting lipids in order to cross cellular membrane barriers. Toward addressing this limitation, our experiments explore the extent to which membrane fusion can be amplified by using the process of lipid membrane phase separation to concentrate fusion-promoting lipids within distinct regions of the membrane surface. We used confocal fluorescence microscopy to investigate the integration of fusion-promoting lipids into a ternary lipid membrane system that separated into liquid-ordered and liquid-disordered membrane phases. Additionally, we quantified the impact of membrane phase separation on the efficiency with which liposomes transferred lipids and encapsulated macromolecules to cells, using a combination of confocal fluorescence imaging and flow cytometry. Here we report that concentrating fusion-promoting lipids within phase-separated lipid domains on the surfaces of liposomes significantly increases the efficiency of liposome fusion with model membranes and cells. In particular, membrane phase separation enhanced the delivery of lipids and model macromolecules to the cytoplasm of tumor cells by at least 4-fold in comparison to homogenous liposomes. Our findings demonstrate that phase separation can enhance membrane fusion by locally concentrating fusion-promoting lipids on the surface of liposomes. This work represents the first application of lipid membrane phase separation in the design of biomaterials-based delivery systems. Additionally, these results lay the ground work for developing fusogenic liposomes that are triggered by physical and

Shear viscosity of phase-separating polymer blends with viscous asymmetry

International Nuclear Information System (INIS)

Jeon, H. S.; Hobbie, E. K.

2001-01-01

Rheo-optical measurements of phase separating polymer mixtures under simple shear flow have been used to investigate the influence of domain morphology on the viscosity of emulsionlike polymer blends, in which the morphology under weak shear is droplets of one coexisting phase dispersed in a matrix of the second. The structure and viscosity of low-molecular-weight polybutadiene and polyisoprene mixtures, phase separated by quenching to a temperature inside the coexistence region of the phase diagram, were measured as a function of shear rate and composition. In the weak shear regime, the data are in qualitative agreement with an effective medium model for non-dilute suspensions of slightly deformed interacting droplets. In the strong shear regime, where a stringlike pattern appears en route to a shear-homogenized state, the data are in qualitative agreement with a simple model that accounts for viscous asymmetry in the components

Solid phase separation technique for use in radioimmunoassays

International Nuclear Information System (INIS)

Tu, J.I.

1979-01-01

A radioimmunoassay procedure, and article of manufacture for carrying out that procedure, are disclosed herein. The solid phase separation technique utilized in the radioimmunoassay of this invention utilizes a test tube, the internal surface of which has been coated with two antibody layers

Lifshitz-Slyozov kinetics of a nonconserved system that separates into phases of different density

DEFF Research Database (Denmark)

Mouritsen, Ole G.; Shah, Peter Jivan; Andersen, Jørgen Vitting

1990-01-01

Computer-simulation techniques are applied to analyze the late-stage ordering kinetics of a two-dimensional annealed dilute Ising model quenched into regions of its phase diagram that involve phase separation of phases with different densities. The order parameter of the model is a nonconserved...... of the phase-separation kinetics in O/W(110) systems at high coverage....

Phase separation in living micellar networks

Science.gov (United States)

Cristobal, G.; Rouch, J.; Curély, J.; Panizza, P.

We present a lattice model based on two n→0 spin vectors, capable of treating the thermodynamics of living networks in micellar solutions at any surfactant concentration. We establish an isomorphism between the coupling constants in the two spin vector Hamiltonian and the surfactant energies involved in the micellar situation. Solving this Hamiltonian in the mean-field approximation allows one to calculate osmotic pressure, aggregation number, free end and cross-link densities at any surfactant concentration. We derive a phase diagram, including changes in topology such as the transition between spheres and rods and between saturated and unsaturated networks. A phase separation can be found between a saturated network and a dilute solution composed of long flexible micelles or a saturated network and a solution of spherical micelles.

A new liquid-phase-separation glaze containing neodymium oxide

International Nuclear Information System (INIS)

Jing, S.; Xianque, C.; Luxing, K.; Pentecost, J.L.

1986-01-01

A color-changeable opaque glaze containing neodymium oxide was investigated. Results show that the glaze is a new example of the liquid-phase-separation type. The discrete phase droplets are from 50 to 500 nm in size. They are rich in Nd, Zn, Ca, and Mg and the continuous phase is rich in Si, Al, and K. The concentration of the discrete phase is approx. =45%. The large number of discrete droplets and the zinc oxide in the glaze increase its opacity to cover the selective light absorption and scattering of the neodymium ion and reduce the opalescence effect

Poly(Ionic Liquid: A New Phase in a Thermoregulated Phase Separated Catalysis and Catalyst Recycling System of Transition Metal-Mediated ATRP

Directory of Open Access Journals (Sweden)

Lan Yao

2018-03-01

Full Text Available Poly(ionic liquids (PILs have become the frontier domains in separation science because of the special properties of ionic liquids as well as their corresponding polymers. Considering their function in separation, we designed and synthesized a thermoregulated PIL. That is, this kind of PIL could separate with an organic phase which dissolves the monomers at ambient temperature. When heated to the reaction temperature, they become a homogeneous phase, and they separate again when the temperature falls to the ambient temperature after polymerization. Based on this, a thermoregulated phase separated catalysis (TPSC system for Cu-based atom transfer radical polymerization (ATRP was constructed. The copper catalyst (CuBr2 used here is easily separated and recycled in situ just by changing the temperature in this system. Moreover, even when the catalyst had been recycled five times, the controllability over resultant polymers is still satisfying. Finally, only 1~2 ppm metal catalyst was left in the polymer solution phase, which indicates the really high recycling efficiency.

Dynamical phase separation using a microfluidic device: experiments and modeling

Science.gov (United States)

Aymard, Benjamin; Vaes, Urbain; Radhakrishnan, Anand; Pradas, Marc; Gavriilidis, Asterios; Kalliadasis, Serafim; Complex Multiscale Systems Team

2017-11-01

We study the dynamical phase separation of a binary fluid by a microfluidic device both from the experimental and from the modeling points of view. The experimental device consists of a main channel (600 μm wide) leading into an array of 276 trapezoidal capillaries of 5 μm width arranged on both sides and separating the lateral channels from the main channel. Due to geometrical effects as well as wetting properties of the substrate, and under well chosen pressure boundary conditions, a multiphase flow introduced into the main channel gets separated at the capillaries. Understanding this dynamics via modeling and numerical simulation is a crucial step in designing future efficient micro-separators. We propose a diffuse-interface model, based on the classical Cahn-Hilliard-Navier-Stokes system, with a new nonlinear mobility and new wetting boundary conditions. We also propose a novel numerical method using a finite-element approach, together with an adaptive mesh refinement strategy. The complex geometry is captured using the same computer-aided design files as the ones adopted in the fabrication of the actual device. Numerical simulations reveal a very good qualitative agreement between model and experiments, demonstrating also a clear separation of phases.

Phase separation in artificial vesicles driven by light and curvature

Science.gov (United States)

Rinaldin, Melissa; Pomp, Wim; Schmidt, Thomas; Giomi, Luca; Kraft, Daniela; Physics of Life Processes Team; Soft; Bio Mechanics Collaboration; Self-Assembly in Soft Matter Systems Collaboration

The role of phase-demixing in living cells, leading to the lipid-raft hypothesis, has been extensively studied. Lipid domains of higher lipid chain order are proposed to regulate protein spatial organization. Giant Unilamellar Vesicles provide an artificial model to study phase separation. So far temperature was used to initiate the process. Here we introduce a new methodology based on the induction of phase separation by light. To this aim, the composition of the lipid membrane is varied by photo-oxidation of lipids. The control of the process gained by using light allowed us to observe vesicle shape fluctuations during phase-demixing. The presence of fluctuations near the critical mixing point resembles features of a critical process. We quantitatively analyze these fluctuations using a 2d elastic model, from which we can estimate the material parameters such as bending rigidity and surface tension, demonstrating the non-equilibrium critical behaviour. Finally, I will describe recent attempts toward tuning the membrane composition by controlling the vesicle curvature.

Hydroxylamine hydrochloride-acetic acid-soluble and -insoluble fractions of pelagic sediment: Readsorption revisited

Science.gov (United States)

Piper, D.Z.; Wandless, G.A.

1992-01-01

The extraction of the rare earth elements (REE) from deep-ocean pelagic sediment, using hydroxylamine hydrochloride-acetic acid, leads to the separation of approximately 70% of the bulk REE content into the soluble fraction and 30% into the insoluble fraction. The REE pattern of the soluble fraction, i.e., the content of REE normalized to average shale on an element-by-element basis and plotted against atomic number, resembles the pattern for seawater, whereas the pattern, as well as the absolute concentrations, in the insoluble fraction resembles the North American shale composite. These results preclude significant readsorption of the REE by the insoluble phases during the leaching procedure.

Ternary Phase-Separation Investigation of Sol-Gel Derived Silica from Ethyl Silicate 40

Science.gov (United States)

Wang, Shengnan; Wang, David K.; Smart, Simon; Diniz da Costa, João C.

2015-01-01

A ternary phase-separation investigation of the ethyl silicate 40 (ES40) sol-gel process was conducted using ethanol and water as the solvent and hydrolysing agent, respectively. This oligomeric silica precursor underwent various degrees of phase separation behaviour in solution during the sol-gel reactions as a function of temperature and H2O/Si ratios. The solution composition within the immiscible region of the ES40 phase-separated system shows that the hydrolysis and condensation reactions decreased with decreasing reaction temperature. A mesoporous structure was obtained at low temperature due to weak drying forces from slow solvent evaporation on one hand and formation of unreacted ES40 cages in the other, which reduced network shrinkage and produced larger pores. This was attributed to the concentration of the reactive sites around the phase-separated interface, which enhanced the condensation and crosslinking. Contrary to dense silica structures obtained from sol-gel reactions in the miscible region, higher microporosity was produced via a phase-separated sol-gel system by using high H2O/Si ratios. This tailoring process facilitated further condensation reactions and crosslinking of silica chains, which coupled with stiffening of the network, made it more resistant to compression and densification. PMID:26411484

Solubility of drugs in aqueous polymeric solution: effect of ovalbumin on microencapsulation process.

Science.gov (United States)

Aziz, Hesham Abdul; Tan, Yvonne Tze Fung; Peh, Kok Khiang

2012-03-01

Microencapsulation of water-soluble drugs using coacervation-phase separation method is very challenging, as these drugs partitioned into the aqueous polymeric solution, resulting in poor drug entrapment. For evaluating the effect of ovalbumin on the microencapsulation of drugs with different solubility, pseudoephedrine HCl, verapamil HCl, propranolol HCl, paracetamol, and curcuminoid were used. In addition, drug mixtures comprising of paracetamol and pseudoephedrine HCl were also studied. The morphology, encapsulation efficiency, particle size, and in vitro release profile were investigated. The results showed that the solubility of the drug determined the ratio of ovalbumin to be used for successful microencapsulation. The optimum ratios of drug, ovalbumin, and gelatin for water-soluble (pseudoephedrine HCl, verapamil HCl, and propranolol HCl), sparingly water-soluble (paracetamol), and water-insoluble (curcuminoid) drugs were found to be 1:1:2, 2:3:5, and 1:3:4. As for the drug mixture, the optimum ratio of drug, ovalbumin, and gelatin was 2:3:5. Encapsulated particles prepared at the optimum ratios showed high yield, drug loading, entrapment efficiency, and sustained release profiles. The solubility of drug affected the particle size of the encapsulated particle. Highly soluble drugs resulted in smaller particle size. In conclusion, addition of ovalbumin circumvented the partitioning effect, leading to the successful microencapsulation of water-soluble drugs.

Short range order and phase separation in Ti-rich Ti-Al alloys

International Nuclear Information System (INIS)

Liew, H.J.

1999-01-01

Many metals and alloys are used in service under conditions in which they are metastable or unstable with respect to phase separation or transformation. Analytical and numerical models exist for relatively simple decomposition processes, such as nucleation and growth mechanisms and spinodal decomposition. In reality, however, more complex phase transformations may occur which are less well understood. For example, reactions involving coupled ordering and phase separation, such as the 'conditional spinodal mechanism', have been predicted. A 'conditional spinodal' is defined as a reaction in which compositional phase separation is thermodynamically possible only after a prior process, such as ordering at the parent composition. There is some debate regarding which real alloy systems exhibit such complex behaviour. Previous atom probe field ion microscopy work on titanium-rich titanium-aluminium based alloys has led to the suggestion that formation of the α 2 phase in this system may occur by a complex phase separation process. As well as being of interest from the point of view of fundamental materials science, this has potential engineering significance as the Ti-Al system forms the basis of the current generation of high-temperature Ti-based alloys for compressor applications in jet engines. This thesis describes an investigation into the phase decomposition process taking place in a titanium-rich Ti-Al alloy lying in the two-phase α+α 2 region. Experimentally, a binary alloy containing 15at% aluminium was heat-treated and examined using electron microscopy, X-ray diffraction, atom probe field ion microscopy and mechanical testing methods. Neutron diffraction experiments were also completed on this system for the first time. In addition, fully three-dimensional atomistic simulations were conducted using a Monte Carlo computer model based on first principles thermodynamic stability calculations of the Ti-Al system. The results provide an insight into many aspects

Thermodynamics of the sorption of water-soluble vitamins in reverse-phase high performance liquid chromatography

Science.gov (United States)

Chirkin, V. A.; Karpov, S. I.; Selemenev, V. F.

2012-12-01

The thermodynamics of the sorption of certain water-soluble vitamins on a C18 reverse phase from water-acetonitrile solutions of different compositions is studied. The thermodynamic characteristics of the investigated chromatographic systems are calculated. The dependences of standard molar enthalpy and changes in entropy when the sorbate transfers from the bulk solution to the surface layer on the concentration of the organic component in the mobile phase are analyzed. The boundaries for applying the main retention models describing the sorption of the investigated compounds are discussed.

Phase separation in an experimental mixer-settler

International Nuclear Information System (INIS)

Eckert, N.L.; Gormely, L.S.

1989-01-01

An experimental investigation was undertaken to study the factors affecting phase separation in a laboratory scale mixer-settler using a laboratory-prepared commercial oxime-copper system, and a system obtained from the Key Lake uranium extraction circuit. Besides being dependent on specific settler flow, the dispersion band thickness was found to be a function of the phase ratio and dispersion introduction level (uranium system only), and temperature. Drop size was found to be independent of dispersion throughout, a weak function of impeller speed, and a relatively strong function of the phase ratio. Microscopic examination of the uranium dispersion revealed the existence of drops within drops. With the exception of the organic continuous copper system, it was possible to distinguish two horizontal sublayers within the dispersion band. This structure conforms to the model provided by Barnea and Mizrahi. (author)

Lamellar-lamellar phase separation of phospholipid bilayers induced by salting-in/-out effects

Energy Technology Data Exchange (ETDEWEB)

Hishida, Mafumi [Institute for Integrated Cell-Material Sciences, Kyoto University, Kyoto 606-8501 (Japan); Seto, Hideki, E-mail: hideki.seto@kek.jp [KENS and CMRC, Institute of Materials Structure Science, High Energy Accelerator Research Organization, Tsukuba 305-0801 (Japan)

2011-01-01

The multilamellar structure of phospholipid bilayers is stabilized by the interactions between bilayers. Although the lamellar repeat distance is uniquely determined at the balance point of interactions between bilayers, a lamellar-lamellar phase separation, where the two phases with different lamellar repeat distance coexist, has been reported in a case of adding a salt to the aqueous solution of lipids. In order to understand the physical mechanism of the lamellar-lamellar phase separation, the effects of adding monovalent salt on the lamellar structure are studied by visual observation and by small-angle X-ray scattering. Further, a theoretical model based on the mean field theory is introduced and it is concluded that the salting-in and -out effects of lipid bilayers trigger the lamellar-lamellar phase separation.

Conception, synthesis and application of tripodands in actinide/lanthanide separation

International Nuclear Information System (INIS)

Bobet, Josselin

1997-01-01

The purpose of this work is the synthesis of C, H, O and N containing compounds able to separate '4f' and '5f' elements by liquid/liquid extraction. In a first part, the literature's study allow us to point out actinide and lanthanide ions actual nature and the different ways offered by organic chemistry to share two metallic ions between two liquid phases. On one hand, these trivalent cations' high coordination numbers drive us to synthesize tripodands with hard sites which were fitted for complexation. On the other hand, it appeared that carboxylate or even less-hard site like pyridine chelate selectively actinides, allowing separation. In a second part, 60 ligands were synthesized. In each of the ligands families, a structural parameter changes (site nature, distance between two neighbouring sites, sites respective orientation, lipophilicity and rigidity). 2,2-dihydroxymethyl-dodecanol and 1,3,5- tri(chlorocarbonyl) benzene were chosen as core. O-alkylation and amidation reactions were also peculiarly studied. Rekker's proceeding for lipophilicity calculation was used in order to establish a structure-activity relationship. In a third part, extraction assays with radioactive effluents ( 152 Eu and 241 Am) point out extraction and separation abilities of our compounds. Different operating ways were used according as ligand is soluble in aqueous or organic phase. Organic phase-soluble compounds were compared to DcH18C6, pyridine ones to 2,4,6-tri(2-pyridyl)-l,3,5-triazine (TPTZ) and carboxylate ones to diethylenetriamine-tetracetic acid (DTPA, Talspeak proceeding). The third phase phenomenon was encountered and studied. Influence of salt, pH and organic phase were also studied. (author) [fr

Macroscopic phase separation in high-temperature superconductors

Science.gov (United States)

Wen, Hai-Hu

2000-01-01

High-temperature superconductivity is recovered by introducing extra holes to the Cu-O planes, which initially are insulating with antiferromagnetism. In this paper I present data to show the macroscopic electronic phase separation that is caused by either mobile doping or electronic instability in the overdoped region. My results clearly demonstrate that the electronic inhomogeneity is probably a general feature of high-temperature superconductors. PMID:11027323

Pointwise asymptotic convergence of solutions for a phase separation model

Czech Academy of Sciences Publication Activity Database

Krejčí, Pavel; Zheng, S.

2006-01-01

Roč. 16, č. 1 (2006), s. 1-18 ISSN 1078-0947 Institutional research plan: CEZ:AV0Z10190503 Keywords : phase-field system * asymptotic phase separation * energy Subject RIV: BA - General Mathematics Impact factor: 1.087, year: 2006 http://aimsciences.org/journals/pdfs.jsp?paperID=1875&mode=full

Monte Carlo simulations of the phase separation of a copolymer blend in a thin film

KAUST Repository

Wang, Zhexiao

2014-12-11

Monte Carlo simulations were carried out to study the phase separation of a copolymer blend comprising an alternating copolymer and/or block copolymer in a thin film, and a phase diagram was constructed with a series of composed recipes. The effects of composition and segregation strength on phase separation were discussed in detail. The chain conformation of the block copolymer and alternating copolymer were investigated with changes of the segregation strength. Our simulations revealed that the segment distribution along the copolymer chain and the segregation strength between coarse-grained beads are two important parameters controlling phase separation and chain conformation in thin films of a copolymer blend. A well-controlled phase separation in the copolymer blend can be used to fabricate novel nanostructures.

Influence of mobile dislocations on phase separation in binary alloys

International Nuclear Information System (INIS)

Haataja, Mikko; Leonard, Francois

2004-01-01

We introduce a continuum model to describe the phase separation of a binary alloy in the presence of mobile dislocations. The kinetics of the local composition and dislocation density are coupled through their elastic fields. We show both analytically and numerically that mobile dislocations modify the standard spinodal decomposition process, and lead to several regimes of growth. Depending on the dislocation mobility and observation time, the phase separation may be accelerated, decelerated, or unaffected by mobile dislocations. For any finite dislocation mobility, we show that the domain growth rate asymptotically becomes independent of the dislocation mobility, and is faster than the dislocation-free growth rate

Synthesis of a mixed-model stationary phase derived from glutamine for HPLC separation of structurally different biologically active compounds: HILIC and reversed-phase applications.

Science.gov (United States)

Aral, Tarık; Aral, Hayriye; Ziyadanoğulları, Berrin; Ziyadanoğulları, Recep

2015-01-01

A novel mixed-mode stationary phase was synthesised starting from N-Boc-glutamine, aniline and spherical silica gel (4 µm, 60 Å). The prepared stationary phase was characterized by IR and elemental analysis. The new stationary phase bears an embedded amide group into phenyl ring, highly polar a terminal amide group and non-polar groups (phenyl and alkyl groups). At first, this new mixed-mode stationary phase was used for HILIC separation of four nucleotides and five nucleosides. The effects of different separation conditions, such as pH value, mobile phase and temperature, on the separation process were investigated. The optimum separation for nucleotides was achieved using HILIC isocratic elution with aqueous mobile phase and acetonitrile with 20°C column temperature. Under these conditions, the four nucleotides could be separated and detected at 265 nm within 14 min. Five nucleosides were separated under HILIC isocratic elution with aqueous mobile phase containing pH=3.25 phosphate buffer (10mM) and acetonitrile with 20°C column temperature and detected at 265 nm within 14 min. Chromatographic parameters as retention factor, selectivity, theoretical plate number and peak asymmetry factor were calculated for the effect of temperature and water content in mobile phase on the separation process. The new column was also tested for nucleotides and nucleosides mixture and six analytes were separated in 10min. The chromatographic behaviours of these polar analytes on the new mixed-model stationary phase were compared with those of HILIC columns under similar conditions. Further, phytohormones and phenolic compounds were separated in order to see influence of the new stationary phase in reverse phase conditions. Eleven plant phytohormones were separated within 13 min using RP-HPLC gradient elution with aqueous mobile phase containing pH=2.5 phosphate buffer (10mM) and acetonitrile with 20°C column temperature and detected at 230 or 278 nm. The best separation

New strategies in actinide separation - water-soluble complexing agents for the innovative SANEX process

International Nuclear Information System (INIS)

Ruff, Christian M.; Muelllich, Udo; Geist, Andreas; Panak, Petra J.

2012-01-01

Reduction of the radiotoxicity and thermal output of radioactive wastes prior to their permanent disposal is a topic of extreme interest for the issue of final nuclear waste disposal. One possibility to this end is a process referred to as actinide separation. This process can be optimised by means of a newly developed water-soluble molecule, as has been shown in studies on the molecule's complex chemistry using ultra-modern laser-based spectroscopy methods under process-relevant reaction conditions. Through the use of curium (III) and europium (III), which as members of the trivalent actinides and lanthanides family have excellent spectroscopic properties, it has been possible to generate spectroscopic and thermodynamic data which will facilitate our understanding of the complex chemistry and extraction chemistry of this molecule family.

Fluid Phase Separation (FPS) experiment for flight on a space shuttle Get Away Special (GAS) canister

Science.gov (United States)

Peters, Bruce; Wingo, Dennis; Bower, Mark; Amborski, Robert; Blount, Laura; Daniel, Alan; Hagood, Bob; Handley, James; Hediger, Donald; Jimmerson, Lisa

1990-01-01

The separation of fluid phases in microgravity environments is of importance to environmental control and life support systems (ECLSS) and materials processing in space. A successful fluid phase separation experiment will demonstrate a proof of concept for the separation technique and add to the knowledge base of material behavior. The phase separation experiment will contain a premixed fluid which will be exposed to a microgravity environment. After the phase separation of the compound has occurred, small samples of each of the species will be taken for analysis on the Earth. By correlating the time of separation and the temperature history of the fluid, it will be possible to characterize the process. The experiment has been integrated into space available on a manifested Get Away Special (GAS) experiment, CONCAP 2, part of the Consortium for Materials Complex Autonomous Payload (CAP) Program, scheduled for STS-42. The design and the production of a fluid phase separation experiment for rapid implementation at low cost is presented.

Ribbon phase in a phase-separated lyotropic lamellar-sponge mixture under shear flow

Science.gov (United States)

Cristobal, G.; Rouch, J.; Panizza, P.; Narayanan, T.

2001-07-01

We report the effect of shear flow on a phase-separated system composed of lyotropic lamellar (Lα) and sponge (L3) phases in a mixture of brine, surfactant, and cosurfactant. Optical microscopy, small-angle light, and x-ray scattering measurements are consistent with the existence of a steady state made of multilamellar ribbonlike structures aligned in the flow direction. At high shear rates, these ribbonlike structures become unstable and break up into monodisperse droplets resulting in a shear-thickening transition.

[Study on extracting and separating curcuminoids from Curcuma longa rhizome using ultrasound strengthen by microemulsion].

Science.gov (United States)

Yue, Chun-Hua; Zheng, Li-Tao; Guo, Qi-Ming; Li, Kun-Ping

2014-05-01

To establish a new method for the extraction and separation of curcuminoids from Curcuma longa rhizome by cloud-point preconcentration using microemulsions as solvent. The spectrophotometry was used to detect the solubility of curcumin in different oil phase, emulsifier and auxiliary emulsifier, and the microemulsion prescription was used for false three-phase figure optimization. The extraction process was optimized by uniform experiment design. The curcuminoids were separated from microemulsion extract by cloud-point preconcentration. Oil phase was oleic acid ethyl ester; Emulsifier was OP emulsifier; Auxiliary emulsifier was polyethylene glycol(peg) 400; The quantity of emulsifier to auxiliary emulsifier was the ratio of 5: 1; Microemulsion prescription was water-oleic acid ethyl ester-mixed emulsifier (0.45:0.1:0.45). The optimum extraction process was: time for 12.5 min, temperature of 52 degrees C, power of 360 W, frequency of 400 kHz, and the liquid-solid ratio of 40:1. The extraction rate of curcuminoids was 92.17% and 86.85% in microemulsion and oil phase, respectively. Curcuminoids is soluble in this microemulsion prescription with good extraction rate. This method is simple and suitable for curcuminoids extraction from Curcuma longa rhizome.

Solid solubility in 1:13 phase of doping element for La(Fe,Si13 alloys

Directory of Open Access Journals (Sweden)

S. T. Zong

2016-05-01

Full Text Available The influences of Ni, Cr and Nb as substitution elements for Fe were investigated. The change in microstructure and the magnetic properties have been discussed in detail. Substitution elements Ni, Cr and Nb not only have limited solubility in NaZn13-type (1:13 phase, but also hinder the peritectoid reaction. Ni element mainly enters into La-rich phase while Cr element mainly concentrates in α-Fe phase, which both have detriment effect on the peritectoid reaction, leading to a large residual of impurity phases after annealing and a decrease of magnetic entropy change. Besides, Ni and Cr participated in peritectoid reaction by entering parent phases but slightly entering 1:13 phase, which would cause the disappearance of first order magnetic phase transition. A new phase (Fe,Si2Nb was found when Nb element substitutes Fe in La(Fe,Si13, suggesting that Nb does not participate in peritectoid reaction and only exists in (Fe,Si2Nb phase after annealing. The alloy with Nb substitution maintains the first order magnetic phase transition character.

High pressure liquid chromatographic method for the separation and quantitation of water-soluble radiolabeled benzene metabolites

International Nuclear Information System (INIS)

Sabourin, P.J.; Bechtold, W.E.; Henderson, R.F.

1988-01-01

The glucuronide and sulfate conjugates of benzene metabolite as well as muconic acid and pre-phenyl- and phenylmercapturic acids were separated by ion-pairing HPLC. The HPLC method developed was suitable for automated analysis of a large number of tissue or excreta samples. p-Nitrophenyl [ 14 C]glucuronide was used as an internal standard for quantitation of these water-soluble metabolites. Quantitation was verified by spiking liver tissue with various amounts of phenylsulfate or glucuronides of phenol, catechol, or hydroquinone and analyzing by HPLC. Values determined by HPLC analysis were within 10% of the actual amount with which the liver was spiked. The amount of metabolite present in urine following exposure to [ 3 H]benzene was determined using p-nitrophenyl [ 14 C]glucuronide as an internal standard. Phenylsulfate was the major water-soluble metabolite in the urine of F344 rats exposed to 50 ppm [ 3 H]benzene for 6 h. Muconic acid and an unknown metabolite which decomposed in acidic media to phenylmercapturic acid were also present. Liver, however, contained a different metabolic profile. This indicates that urinary metabolite profiles may not be a true reflection of what is seen in individual tissues

Negative heat capacity at phase-separation in macroscopic systems

OpenAIRE

Gross, D. H. E.

2005-01-01

Systems with long-range as well with short-range interactions should necessarily have a convex entropy S(E) at proper phase transitions of first order, i.e. when a separation of phases occurs. Here the microcanonical heat capacity c(E)= -\\frac{(\\partial S/\\partial E)^2}{\\partial^2S/\\partial E^2} is negative. This should be observable even in macroscopic systems when energy fluctuations with the surrounding world can be sufficiently suppressed.

Homogeneous nucleation in phase separation of solid 3He-4He mixtures

International Nuclear Information System (INIS)

Poole, M.; Smith, A.; Maidanov, V.A.; Rudavskii, E.Ya.; Grigor'ev, V.N.; Slezov, V.V.; Saunders, J.; Cowan, B.

2003-01-01

NMR and pressure have been measured during phase separation in solid 3 He- 4 He mixtures. Spin echoes were used to observe bounded diffusion and to estimate the diffusion coefficient, size and nuclei concentration in the 3 He-enriched phase. The characteristic phase separation time constant of the mixture was found from pressure measurements. The results argue convincingly for homogeneous nucleation. The surface tension of the nuclei is found independently from NMR and from pressure measurements; the two determinations agree well and yield a surface tension coefficient of 4.9x10 -6 J m -2

Lateral phase separation of mixed polymer brushes on planar and spherical surfaces

Science.gov (United States)

van Lehn, Reid; Alexander-Katz, Alfredo

2012-02-01

A mixed polymer brush consists of two (or more) polymer species grafted to a surface at a high density, inducing the polymers to highly stretch to maximize favorable solvent interactions while minimizing polymer overlap. The enthalpic and entropic interactions between the different polymers give rise to lateral phase behavior on the surface. Understanding this phase separation behavior is interesting for applications in nanotemplating and controlled protein adsorption. In this work, we present a novel theoretical model to quickly predict lateral phase separated morphologies of mixed polymer brushes on planar, cylindrical and spherical surfaces. The model combines a Flory-Huggins model for enthalpic interactions between the polymer components with an Alexander-de Gennes model for the entropy of the brush layers. When there is a length difference between the polymer components, these two interactions along with the conformational entropy of the system lead to a range of morphologies including stripes, dimples, mixing, and complete phase separation. The computational efficiency of this model allows for phase diagrams to be generated with great accuracy. The results of our model thus allow for the fast prediction of lateral morphologies on different geometries.

Self-assembly of amorphous biophotonic nanostructures by phase separation

Energy Technology Data Exchange (ETDEWEB)

Dufresne, Eric R.; Noh, Heeso; Saranathan, Vinodkumar; Mochrie, Simon G.J.; Cao, Hui; Prum, Richard O.; (Yale)

2009-04-23

Some of the most vivid colors in the animal kingdom are created not by pigments, but by wavelength-selective scattering of light from nanostructures. Here we investigate quasi-ordered nanostructures of avian feather barbs which produce vivid non-iridescent colors. These {beta}-keratin and air nanostructures are found in two basic morphologies: tortuous channels and amorphous packings of spheres. Each class of nanostructure is isotropic and has a pronounced characteristic length scale of variation in composition. These local structural correlations lead to strong backscattering over a narrow range of optical frequencies and little variation with angle of incidence. Such optical properties play important roles in social and sexual communication. To be effective, birds need to precisely control the development of these nanoscale structures, yet little is known about how they grow. We hypothesize that multiple lineages of birds have convergently evolved to exploit phase separation and kinetic arrest to self-assemble spongy color-producing nanostructures in feather barbs. Observed avian nanostructures are strikingly similar to those self-assembled during the phase separation of fluid mixtures; the channel and sphere morphologies are characteristic of phase separation by spinodal decomposition and nucleation and growth, respectively. These unstable structures are locked-in by the kinetic arrest of the {beta}-keratin matrix, likely through the entanglement or cross-linking of supermolecular {beta}-keratin fibers. Using the power of self-assembly, birds can robustly realize a diverse range of nanoscopic morphologies with relatively small physical and chemical changes during feather development.

Effect of heat treatment duration on phase separation of sodium borosilicate glass, containing copper

International Nuclear Information System (INIS)

Shejnina, T.G.; Gutner, S.Kh.; Anan'in, N.I.

1989-01-01

The effect of heat treatment duration on phase separation of sodium borosilicate (SBS) glass, containing copper is studied. It is stated that phase separation close to equilibrium one is attained under 12 hours of heat treatment of SBS glass containing copper

Exploring the dynamics of phase separation in colloid-polymer mixtures with long range attraction.

Science.gov (United States)

Sabin, Juan; Bailey, Arthur E; Frisken, Barbara J

2016-06-28

We have studied the kinetics of phase separation and gel formation in a low-dispersity colloid - non-adsorbing polymer system with long range attraction using small-angle light scattering. This system exhibits two-phase and three-phase coexistence of gas, liquid and crystal phases when the strength of attraction is between 2 and 4kBT and gel phases when the strength of attraction is increased. For those samples that undergo macroscopic phase separation, whether to gas-crystal, gas-liquid or gas-liquid-crystal coexistence, we observe dynamic scaling of the structure factor and growth of a characteristic length scale that behaves as expected for phase separation in fluids. In samples that gel, the power law associated with the growth of the dominant length scale is not equal to 1/3, but appears to depend mainly on the strength of attraction, decreasing from 1/3 for samples near the coexistence region to 1/27 at 8kBT, over a wide range of colloid and polymer concentrations.

1D and 2D NMR Spectroscopy of Bonding Interactions within Stable and Phase-Separating Organic Electrolyte-Cellulose Solutions.

Science.gov (United States)

Clough, Matthew T; Farès, Christophe; Rinaldi, Roberto

2017-09-11

Organic electrolyte solutions (i.e. mixtures containing an ionic liquid and a polar, molecular co-solvent) are highly versatile solvents for cellulose. However, the underlying solvent-solvent and solvent-solute interactions are not yet fully understood. Herein, mixtures of the ionic liquid 1-ethyl-3-methylimidazolium acetate, the co-solvent 1,3-dimethyl-2-imidazolidinone, and cellulose are investigated using 1D and 2D NMR spectroscopy. The use of a triply- 13 C-labelled ionic liquid enhances the signal-to-noise ratio for 13 C NMR spectroscopy, enabling changes in bonding interactions to be accurately pinpointed. Current observations reveal an additional degree of complexity regarding the distinct roles of cation, anion, and co-solvent toward maintaining cellulose solubility and phase stability. Unexpectedly, the interactions between the dialkylimidazolium ring C 2 -H substituent and cellulose become more pronounced at high temperatures, counteracted by a net weakening of acetate-cellulose interactions. Moreover, for mixtures that exhibit critical solution behavior, phase separation is accompanied by the apparent recombination of cation-anion pairs. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Preparation and Characterization of Silicone Liquid Core/Polymer Shell Microcapsules via Internal Phase Separation

DEFF Research Database (Denmark)

Gonzalez, Lidia; Kostrzewska, Malgorzata; Ma, Baoguang

2014-01-01

Microcapsules with a silicone liquid core surrounded by a polymeric shell were synthesisedthrough the controlled phase separation. The dispersed silicone phase consisted of the shellpolymer PMMA, a good solvent for the PMMA (dichloromethane, DCM) and a poor solvent(methylhydrosiloxane dimethylsil......Microcapsules with a silicone liquid core surrounded by a polymeric shell were synthesisedthrough the controlled phase separation. The dispersed silicone phase consisted of the shellpolymer PMMA, a good solvent for the PMMA (dichloromethane, DCM) and a poor solvent...

Design and Development of Gas-Liquid Cylindrical Cyclone Compact Separators for Three-Phase Flow; SEMIANNUAL

International Nuclear Information System (INIS)

Mohan, Ram S.; Shoham, Ovadia

1999-01-01

The objective of this five-year project (October, 1997-September, 2002) is to expand the current research activities of Tulsa University Separation Technology Projects (TUSTP) to multiphase oil/water/gas separation. This project will be executed in two phases. Phase I (1997-2000) will focus on the investigations of the complex multiphase hydrodynamic flow behavior in a three-phase Gas-Liquid Cylindrical Cyclone (GLCC) Separator. The activities of this phase will include the development of a mechanistic model, a computational fluid dynamics (CFD) simulator, and detailed experimentation on the three-phase GLCC. The experimental and CFD simulation results will be suitably integrated with the mechanistic model. In Phase II (2000-2002), the developed GLCC separator will be tested under high pressure and real crudes conditions. This is crucial for validating the GLCC design for field application and facilitating easy and rapid technology deployment. Design criteria for industrial applications will be developed based on these results and will be incorporated into the mechanistic model by TUSTP

The Two-Phase Flow Separator Experiment Breadboard Model: Reduced Gravity Aircraft Results

Science.gov (United States)

Rame, E; Sharp, L. M.; Chahine, G.; Kamotani, Y.; Gotti, D.; Owens, J.; Gilkey, K.; Pham, N.

2015-01-01

Life support systems in space depend on the ability to effectively separate gas from liquid. Passive cyclonic phase separators use the centripetal acceleration of a rotating gas-liquid mixture to carry out phase separation. The gas migrates to the center, while gas-free liquid may be withdrawn from one of the end plates. We have designed, constructed and tested a breadboard that accommodates the test sections of two independent principal investigators and satisfies their respective requirements, including flow rates, pressure and video diagnostics. The breadboard was flown in the NASA low-gravity airplane in order to test the system performance and design under reduced gravity conditions.

Phase separation of bio-oil produced by co-pyrolysis of corn cobs and polypropylene

Science.gov (United States)

Supramono, D.; Julianto; Haqqyana; Setiadi, H.; Nasikin, M.

2017-11-01

In co-pyrolysis of biomass-plastics, bio-oil produced contains both oxygenated and non-oxygenated compounds. High oxygen composition is responsible for instability and low heating value of bio-oil and high acid content for corrosiveness. Aims of the present work are to evaluate possibilities of achieving phase separation between oxygenated and non-oxygenated compounds in bio-oil using a proposed stirred tank reactor and to achieve synergistic effects on bio-oil yield and non-oxygenated compound layer yield. Separation of bio-oil into two layers, i.e. that containing oxygenated compounds (polar phase) and non-oxygenated compounds (non-polar phase) is important to obtain pure non-polar phase ready for the next processing of hydrogenation and used directly as bio-fuel. There has been no research work on co-pyrolysis of biomass-plastic considering possibility of phase separation of bio-oil. The present work is proposing a stirred tank reactor for co-pyrolysis with nitrogen injection, which is capable of tailoring co-pyrolysis conditions leading to low viscosity and viscosity asymmetry, which induce phase separation between polar phase and non-polar phase. The proposed reactor is capable of generating synergistic effect on bio-oil and non-polar yields as the composition of PP in feed is more than 25% weight in which non-polar layers contain only alkanes, alkenes, cycloalkanes and cycloalkenes.

Sub/supercritical carbon dioxide induced phase switching for the reaction and separation in ILs/methanol

Directory of Open Access Journals (Sweden)

Jiayu Xin

2016-07-01

Full Text Available Separation of products from ionic liquid (IL solvents is one of the main challenges that hinder their utilizations. In this study, the production of γ-valerolactone (GVL by selective hydrogenation of α-angelica lactone (AL and separation of the products from the IL solvent were carried out by using subcritical CO2 as a “switch” at room temperature. After the mixture was separated into two phases by subcritical CO2, AL and nano Pd/C catalyst were only found in the lower IL-rich phase, GVL was produced with quantitative yield and enriched in the upper methanol-rich phase. Pure GVL can be obtained by depressurizing to release CO2 and evaporation to remove methanol of the upper phase, the lower phase containing IL, catalyst and methanol can be recycled for the next reaction. The strategy may provide a new approach to produce and separate products from IL solvents at mild conditions. Keywords: Separation, Ionic liquids, Selective hydrogenation, Mild condition, Subcritical CO2

Enantiomeric separation of type I and type II pyrethroid insecticides with different chiral stationary phases by reversed-phase high-performance liquid chromatography.

Science.gov (United States)

Zhang, Ping; Yu, Qian; He, Xiulong; Qian, Kun; Xiao, Wei; Xu, Zhifeng; Li, Tian; He, Lin

2018-04-01

The enantiomeric separation of type I (bifenthrin, BF) and type II (lambda-cyhalothrin, LCT) pyrethroid insecticides on Lux Cellulose-1, Lux Cellulose-3, and Chiralpak IC chiral columns was investigated by reversed-phase high-performance liquid chromatography. Methanol/water or acetonitrile/water was used as mobile phase at a flow rate of 0.8 mL/min. The effects of chiral stationary phase, mobile phase composition, column temperature, and thermodynamic parameters on enantiomer separation were carefully studied. Bifenthrin got a partial separation on Lux Cellulose-1 column and baseline separation on Lux Cellulose-3 column, while LCT enantiomers could be completely separated on both Lux Cellulose-1 and Lux Cellulose-3 columns. Chiralpak IC provided no separation ability for both BF and LCT. Retention factor (k) and selectivity factor (α) decreased with the column temperature increasing from 10°C to 40°C for both BF and LCT enantiomers. Thermodynamic parameters including ∆H and ∆S were also calculated, and the maximum R s were not always obtained at lowest temperature. Furthermore, the quantitative analysis methods for BF and LCT enantiomers in soil and water were also established. Such results provide a new approach for pyrethroid separation under reversed-phase condition and contribute to environmental risk assessment of pyrethroids at enantiomer level. © 2017 Wiley Periodicals, Inc.

Recent progress of chiral stationary phases for separation of enantiomers in gas chromatography.

Science.gov (United States)

Xie, Sheng-Ming; Yuan, Li-Ming

2017-01-01

Chromatography techniques based on chiral stationary phases are widely used for the separation of enantiomers. In particular, gas chromatography has developed rapidly in recent years due to its merits such as fast analysis speed, lower consumption of stationary phases and analytes, higher column efficiency, making it a better choice for chiral separation in diverse industries. This article summarizes recent progress of novel chiral stationary phases based on cyclofructan derivatives and chiral porous materials including chiral metal-organic frameworks, chiral porous organic frameworks, chiral inorganic mesoporous materials, and chiral porous organic cages in gas chromatography, covering original research papers published since 2010. The chiral recognition properties and mechanisms of separation toward enantiomers are also introduced. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Solubility Part 1

NARCIS (Netherlands)

Tantra, Ratna; Bolea, Eduardo; Bouwmeester, H.; Rey-Castro, Carlos; David, C.A.A.; Dogné, Jean Michel; Laborda, Francisco; Laloy, Julie; Robinson, Kenneth N.; Undas, A.K.; Zande, van der M.

2016-01-01

This chapter gives an overview of different methods that can potentially be used to determine the solubility of nanomaterials. In general, the methods presented can be broadly divided into four categories: separation methods, methods to quantify free ions, methods to quantify total dissolved

Control over phase separation and nucleation using a laser-tweezing potential

Science.gov (United States)

Walton, Finlay; Wynne, Klaas

2018-05-01

Control over the nucleation of new phases is highly desirable but elusive. Even though there is a long history of crystallization engineering by varying physicochemical parameters, controlling which polymorph crystallizes or whether a molecule crystallizes or forms an amorphous precipitate is still a poorly understood practice. Although there are now numerous examples of control using laser-induced nucleation, the absence of physical understanding is preventing progress. Here we show that the proximity of a liquid-liquid critical point or the corresponding binodal line can be used by a laser-tweezing potential to induce concentration gradients. A simple theoretical model shows that the stored electromagnetic energy of the laser beam produces a free-energy potential that forces phase separation or triggers the nucleation of a new phase. Experiments in a liquid mixture using a low-power laser diode confirm the effect. Phase separation and nucleation using a laser-tweezing potential explains the physics behind non-photochemical laser-induced nucleation and suggests new ways of manipulating matter.

Simultaneous quantification of 21 water soluble vitamin circulating forms in human plasma by liquid chromatography-mass spectrometry.

Science.gov (United States)

Meisser Redeuil, Karine; Longet, Karin; Bénet, Sylvie; Munari, Caroline; Campos-Giménez, Esther

2015-11-27

This manuscript reports a validated analytical approach for the quantification of 21 water soluble vitamins and their main circulating forms in human plasma. Isotope dilution-based sample preparation consisted of protein precipitation using acidic methanol enriched with stable isotope labelled internal standards. Separation was achieved by reversed-phase liquid chromatography and detection performed by tandem mass spectrometry in positive electrospray ionization mode. Instrumental lower limits of detection and quantification reached water soluble vitamins in human plasma single donor samples. The present report provides a sensitive and reliable approach for the quantification of water soluble vitamins and main circulating forms in human plasma. In the future, the application of this analytical approach will give more confidence to provide a comprehensive assessment of water soluble vitamins nutritional status and bioavailability studies in humans. Copyright © 2015 Elsevier B.V. All rights reserved.

Rapid separation of lanthanides and actinides on small particle based reverse phase supports

Energy Technology Data Exchange (ETDEWEB)

Datta, A.; Sivaraman, N.; Srinivasan, T.G.; Vasudeva Rao, P.R. [Chemistry Group, Indira Gandhi Centre for Atomic Research, Kalpakkam (India)

2010-07-01

This paper presents the results on the use of short columns (3-5 cm long) with small particle size (1.8 {mu}m) for high performance liquid chromatographic separation of individual lanthanides and uranium from plutonium as well as uranium from thorium to achieve rapid separations i.e. separation time as short as 3.6 min for individual lanthanides, 1 min for thorium-uranium and 4.2 min for uranium from plutonium. These advantages can be exploited to significantly reduce analysis time, liquid waste generation as well as dose to operator when radioactive samples are analysed e.g. burn-up determination. In the present work, a dynamic ion-exchange chromatographic separation technique was employed using camphor-10-sulfonic acid (CSA) as the ion-pairing reagent and {alpha}-hydroxy isobutyric acid ({alpha}-HIBA) as the complexing reagent for the isolation of individual lanthanides as well as the separation of uranium from thorium. Uranium was separated from Pu(III) as well as Pu(IV) by reverse phase HPLC technique. The reverse phase HPLC was also investigated for the isolation and quantitative determination of uranium from thorium as well as lanthanide group from uranium. The dynamic ion-exchange technique using small particle support was demonstrated for measuring the concentrations of lanthanide fission products such as La, Ce, Pr, Nd and Sm in the dissolver solution of fast reactor fuel. Similarly, the assay of uranium in the dissolver solution of fast reactor was carried out using reverse phase HPLC technique. The rapid separation technique using reverse phase HPLC was also demonstrated for separation of lanthanides as a group from uranium matrix; samples of LiCl-KCl eutectic salt containing chlorides of lanthanides in uranium matrix (typically 1: 2000) were analysed. (orig.)

Copolymer-grafted silica phase from a cation-anion monomer pair for enhanced separation in reversed-phase liquid chromatography.

Science.gov (United States)

Mallik, Abul K; Qiu, Hongdeng; Takafuji, Makoto; Ihara, Hirotaka

2014-05-01

This work reports a new imidazolium and L-alanine derived copolymer-grafted silica stationary phase for ready separation of complex isomers using high-performance liquid chromatography (HPLC). For this purpose, 1-allyl-3-octadecylimidazolium bromide ([AyImC18]Br) and N-acryloyl-L-alanine sodium salt ([AAL]Na) ionic liquids (IL) monomers were synthesized. Subsequently, the bromide counteranion was exchanged with the 2-(acrylamido)propanoate organic counteranion by reacting the [AyImC18]Br with excess [AAL]Na in water. The obtained IL cation-anion monomer pair was then copolymerized on mercaptopropyl-modified silica (Sil-MPS) via a surface-initiated radical chain-transfer reaction. The selective retention behaviors of polycyclic aromatic hydrocarbons (PAHs), including some positional isomers, steroids, and nucleobases were investigated using the newly obtained Sil-poly(ImC18-AAL), and octadecyl silylated silica (ODS) was used as the reference column. Interesting results were obtained for the separation of PAHs, steroids, and nucleobases with the new organic phase. The results showed that the Sil-poly(ImC18-AAL) presented multiple noncovalent interactions, including hydrophobic, π-π, carbonyl-π, and ion-dipole interactions for the separation of PAHs and dipolar compounds. Only pure water was sufficient as the mobile phase for the separation of the nucleobases. Ten nucleosides and bases were separated, using only water as the mobile phase, within a very short time using the Sil-poly(ImC18-AAL), which is otherwise difficult to achieve using conventional hydrophobic columns such as ODS. The combination of electrostatic and hydrophobic interactions are important for the effective separation of such basic compounds without the use of any organic additive as the eluent on the Sil-poly(ImC18-AAL) column.

Simultaneous determination of water-soluble vitamins in beverages and dietary supplements by LC-MS/MS.

Science.gov (United States)

Kakitani, Ayano; Inoue, Tomonori; Matsumoto, Keiko; Watanabe, Jun; Nagatomi, Yasushi; Mochizuki, Naoki

2014-01-01

An LC-MS/MS method was developed for the simultaneous determination of 15 water-soluble vitamins that are widely used as additives in beverages and dietary supplements. This combined method involves the following simple pre-treatment procedures: dietary supplement samples were prepared by centrifugation and filtration after an extraction step, whereas beverage samples were diluted prior to injection. Chromatographic analysis in this method utilised a multi-mode ODS column, which provided reverse-phase, anion- and cation-exchange capacities, and therefore improved the retention of highly polar analytes such as water-soluble vitamins. Additionally, the multi-mode ODS column did not require adding ion pair reagents to the mobile phase. We optimised the chromatographic separation of 15 water-soluble vitamins by adjusting the mobile phase pH and the organic solvent. We also conducted an analysis of a NIST Standard Reference Material (SRM 3280 Multi-vitamin/Multi-element tablets) using this method to verify its accuracy. In addition, the method was applied to identify the vitamins in commercial beverages and dietary supplements. By comparing results with the label values and results obtained by official methods, it was concluded that the method could be used for quality control and to compose nutrition labels for vitamin-enriched products.

Chelating water-soluble polymers for waste minimization

International Nuclear Information System (INIS)

Smith, B.; Cournoyer, M.; Duran, B.; Ford, D.; Gibson, R.; Lin, M.; Meck, A.; Robinson, P.; Robison, T.

1996-01-01

Within the DOE complex and in industry there is a tremendous need for advanced metal ion recovery and waste minimization techniques. This project sought to employ capabilities for ligand-design and separations chemistry in which one can develop and evaluate water- soluble chelating polymers for recovering actinides and toxic metals from various process streams. Focus of this work was (1) to develop and select a set of water-soluble polymers suitable for a selected waste stream and (2) demonstrate this technology in 2 areas: removal of (a) actinides and toxic RCRA metals from waste water and (b) recovery of Cu and other precious metals from industrial process streams including from solid catalysts and aqueous waste streams. The R ampersand D was done in 4 phases for each of the 2 target areas: polymer synthesis for scaleup, equipment assembly, process demonstration at a DOE or industrial site, and advanced ligand/polymer synthesis. The TA- 50 site at Los Alamos was thought to be appropriate due to logistics and to its being representative of similar problems throughout the DOE complex

Magnetic filtration of phase separating ferrofluids: From basic concepts to microfluidic device

Science.gov (United States)

Kuzhir, P.; Magnet, C.; Ezzaier, H.; Zubarev, A.; Bossis, G.

2017-06-01

In this work, we briefly review magnetic separation of ferrofluids composed of large magnetic particles (60 nm of the average size) possessing an induced dipole moment. Such ferrofluids exhibit field-induced phase separation at relatively low particle concentrations (∼0.8 vol%) and magnetic fields (∼10 kA/m). Particle aggregates appearing during the phase separation are extracted from the suspending fluid by magnetic field gradients much easier than individual nanoparticles in the absence of phase separation. Nanoparticle capture by a single magnetized microbead and by multi-collector systems (packed bed of spheres and micro-pillar array) has been studied both experimentally and theoretically. Under flow and magnetic fields, the particle capture efficiency Λ decreases with an increasing Mason number for all considered geometries. This decrease may become stronger for aggregated magnetic particles (Λ ∝Ma-1.7) than for individual ones (Λ ∝Ma-1) if the shear fields are strong enough to provoke aggregate rupture. These results can be useful for development of new magneto-microfluidic immunoassays based on magnetic nanoparticles offering a much better sensitivity as compared to presently used magnetic microbeads.

Nano-phase separation and structural ordering in silica-rich mixed network former glasses.

Science.gov (United States)

Liu, Hao; Youngman, Randall E; Kapoor, Saurabh; Jensen, Lars R; Smedskjaer, Morten M; Yue, Yuanzheng

2018-06-13

We investigate the structure, phase separation, glass transition, and crystallization in a mixed network former glass series, i.e., B2O3-Al2O3-SiO2-P2O5 glasses with varying SiO2/B2O3 molar ratio. All the studied glasses exhibit two separate glassy phases: droplet phase (G1) with the size of 50-100 nm and matrix phase (G2), corresponding to a lower calorimetric glass transition temperature (Tg1) and a higher one (Tg2), respectively. Both Tg values decrease linearly with the substitution of B2O3 for SiO2, but the magnitude of the decrease is larger for Tg1. Based on nuclear magnetic resonance and Raman spectroscopy results, we infer that the G1 phase is rich in boroxol rings, while the G2 phase mainly involves the B-O-Si network. Both phases contain BPO4- and AlPO4-like units. Ordered domains occur in G2 upon isothermal and dynamic heating, driven by the structural heterogeneity in the as-prepared glasses. The structural ordering lowers the activation energy of crystal growth, thus promoting partial crystallization of G2. These findings are useful for understanding glass formation and phase separation in mixed network former oxide systems, and for tailoring their properties.

Development of the Two Phase Flow Separator Experiment for a Reduced Gravity Aircraft Flight

Science.gov (United States)

Golliher, Eric; Gotti, Daniel; Owens, Jay; Gilkey, Kelly; Pham, Nang; Stehno, Philip

2016-01-01

The recent hardware development and testing of a reduced gravity aircraft flight experiment has provided valuable insights for the future design of the Two Phase Flow Separator Experiment (TPFSE). The TPFSE is scheduled to fly within the Fluids Integration Rack (FIR) aboard the International Space Station (ISS) in 2020. The TPFSE studies the operational limits of gas and liquid separation of passive cyclonic separators. A passive cyclonic separator utilizes only the inertia of the incoming flow to accomplish the liquid-gas separation. Efficient phase separation is critical for environmental control and life support systems, such as recovery of clean water from bioreactors, for long duration human spaceflight missions. The final low gravity aircraft flight took place in December 2015 aboard NASA's C9 airplane.

Facile fabrication of multilayer separators for lithium-ion battery via multilayer coextrusion and thermal induced phase separation

Science.gov (United States)

Li, Yajie; Pu, Hongting

2018-04-01

Polypropylene (PP)/polyethylene (PE) multilayer separators with cellular-like submicron pore structure for lithium-ion battery are efficiently fabricated by the combination of multilayer coextrusion (MC) and thermal induced phase separation (TIPS). The as-prepared separators, referred to as MC-TIPS PP/PE, not only show efficacious thermal shutdown function and wider shutdown temperature window, but also exhibit higher thermal stability than the commercial separator with trilayer construction of PP and PE (Celgard® 2325). The dimensional shrinkage of MC-TIPS PP/PE can be negligible until 160 °C. In addition, compared to the commercial separator, MC-TIPS PP/PE exhibits higher porosity and electrolyte uptake, leading to higher ionic conductivity and better battery performances. The above-mentioned fascinating characteristics with the convenient preparation process make MC-TIPS PP/PE a promising candidate for the application as high performance lithium-ion battery separators.

Rate-induced solubility and suppression of the first-order phase transition in olivine LiFePO4.

Science.gov (United States)

Zhang, Xiaoyu; van Hulzen, Martijn; Singh, Deepak P; Brownrigg, Alex; Wright, Jonathan P; van Dijk, Niels H; Wagemaker, Marnix

2014-05-14

The impact of ultrahigh (dis)charge rates on the phase transition mechanism in LiFePO4 Li-ion electrodes is revealed by in situ synchrotron diffraction. At high rates the solubility limits in both phases increase dramatically, causing a fraction of the electrode to bypass the first-order phase transition. The small transforming fraction demonstrates that nucleation rates are consequently not limiting the transformation rate. In combination with the small fraction of the electrode that transforms at high rates, this indicates that higher performances may be achieved by further optimizing the ionic/electronic transport in LiFePO4 electrodes.

Carrier effect on separation efficiency of the column in reversed-phase partition chromatography

International Nuclear Information System (INIS)

Pszonicka, M.; Siekierski, S.

1972-01-01

Chromatographic columns were filled with carriers of diatomaceous earth type (Hyflo Super Cell, and Celite 545) of large pores, and two microporous silica gels respectively. These columns were used for the separation of europium and gadolinium by reversed-phase partition chromatography in the system: stationary phase-diethylhexylphosphoric acid (HDEHP) mobile phase-0.4 N nitric acid. In each case the separation of the above mentioned elements was achieved. The plate height that characterizes separation efficiency of the column, decreases with the decrease of particle diameter of the carrier. Best columns were obtained from carriers of large pores (Hyflo Super Cell and Celite 545) for which plate hights below 0.1 mm could be achieved. Columns filled with microporous silica gels showed plate heights of 0.2-0.3 mm. (author)

Pharmaceutical Perspective on Opalescence and Liquid-Liquid Phase Separation in Protein Solutions.

Science.gov (United States)

Raut, Ashlesha S; Kalonia, Devendra S

2016-05-02

Opalescence in protein solutions reduces aesthetic appeal of a formulation and can be an indicator of the presence of aggregates or precursor to phase separation in solution signifying reduced product stability. Liquid-liquid phase separation of a protein solution into a protein-rich and a protein-poor phase has been well-documented for globular proteins and recently observed for monoclonal antibody solutions, resulting in physical instability of the formulation. The present review discusses opalescence and liquid-liquid phase separation (LLPS) for therapeutic protein formulations. A brief discussion on theoretical concepts based on thermodynamics, kinetics, and light scattering is presented. This review also discusses theoretical concepts behind intense light scattering in the vicinity of the critical point termed as "critical opalescence". Both opalescence and LLPS are affected by the formulation factors including pH, ionic strength, protein concentration, temperature, and excipients. Literature reports for the effect of these formulation factors on attractive protein-protein interactions in solution as assessed by the second virial coefficient (B2) and the cloud-point temperature (Tcloud) measurements are also presented. The review also highlights pharmaceutical implications of LLPS in protein solutions.

On the Phase Separation in n-Type Thermoelectric Half-Heusler Materials

Directory of Open Access Journals (Sweden)

Michael Schwall

2018-04-01

Full Text Available Half-Heusler compounds have been in focus as potential materials for thermoelectric energy conversion in the mid-temperature range, e.g., as in automotive or industrial waste heat recovery, for more than ten years now. Because of their mechanical and thermal stability, these compounds are advantageous for common thermoelectric materials such as Bi 2 Te 3 , SiGe, clathrates or filled skutterudites. A further advantage lies in the tunability of Heusler compounds, allowing one to avoid expensive and toxic elements. Half-Heusler compounds usually exhibit a high electrical conductivity σ , resulting in high power factors. The main drawback of half-Heusler compounds is their high lattice thermal conductivity. Here, we present a detailed study of the phase separation in an n-type Heusler materials system, showing that the Ti x Zr y Hf z NiSn system is not a solid solution. We also show that this phase separation is key to the thermoelectric high efficiency of n-type Heusler materials. These results strongly underline the importance of phase separation as a powerful tool for designing highly efficient materials for thermoelectric applications that fulfill the industrial demands of a thermoelectric converter.

Doping Induced Transition from an Antiferro-Type Order to Phase Separation

International Nuclear Information System (INIS)

Lemanski, R.; Gajek, Z.

2003-01-01

A sequence of transitions from an antiferro-type order to a phase separate state under doping away from half filling is studied within the 1D Falicov-Kimball model. Using the method of restricted phase diagrams the system is analyzed exactly in the thermodynamic limit. Various kinds of ordering, including periodic n-molecular phases and their mixtures are found for a set of values of the interaction constant U. (author)

Effects of Particles Collision on Separating Gas–Particle Two-Phase Turbulent Flows

KAUST Repository

Sihao, L. V.; Yang, Weihua; Li, Xiangli; Li, Guohui

2013-01-01

A second-order moment two-phase turbulence model incorporating a particle temperature model based on the kinetic theory of granular flow is applied to investigate the effects of particles collision on separating gas–particle two-phase turbulent

Dual Phase Membrane for High Temperature CO2 Separation

Energy Technology Data Exchange (ETDEWEB)

Jerry Lin

2007-06-30

This project aimed at synthesis of a new inorganic dual-phase carbonate membrane for high temperature CO{sub 2} separation. Metal-carbonate dual-phase membranes were prepared by the direct infiltration method and the synthesis conditions were optimized. Permeation tests for CO{sub 2} and N{sub 2} from 450-750 C showed very low permeances of those two gases through the dual-phase membrane, which was expected due to the lack of ionization of those two particular gases. Permeance of the CO{sub 2} and O{sub 2} mixture was much higher, indicating that the gases do form an ionic species, CO{sub 3}{sup 2-}, enhancing transport through the membrane. However, at temperatures in excess of 650 C, the permeance of CO{sub 3}{sup 2-} decreased rapidly, while predictions showed that permeance should have continued to increase with temperature. XRD data obtained from used membrane indicated that lithium iron oxides formed on the support surface. This lithium iron oxide layer has a very low conductivity, which drastically reduces the flow of electrons to the CO{sub 2}/O{sub 2} gas mixture; thus limiting the formation of the ionic species required for transport through the membrane. These results indicated that the use of stainless steel supports in a high temperature oxidative environment can lead to decreased performance of the membranes. This revelation created the need for an oxidation resistant support, which could be gained by the use of a ceramic-type membrane. Work was extended to synthesize a new inorganic dual-phase carbonate membrane for high temperature CO{sub 2} separation. Helium permeance of the support before and after infiltration of molten carbonate are on the order of 10{sup -6} and 10{sup -10} moles/m{sup 2} {center_dot} Pa {center_dot} s respectively, indicating that the molten carbonate is able to sufficiently infiltrate the membrane. It was found that La{sub 0.6}Sr{sub 0.4}Co{sub 0.8}Fe{sub 0.2}O{sub 3-{delta}} (LSCF) was a suitable candidate for the support

Correlated lateral phase separations in stacks of lipid membranes

Energy Technology Data Exchange (ETDEWEB)

Hoshino, Takuma, E-mail: hoshino-takuma@ed.tmu.ac.jp [Department of Chemistry, Graduate School of Science and Engineering, Tokyo Metropolitan University, Tokyo 192-0397 (Japan); Raymond and Beverly Sackler School of Physics and Astronomy, Tel Aviv University, Ramat Aviv, Tel Aviv 69978 (Israel); Kavli Institute for Theoretical Physics China, CAS, Beijing 100190 (China); Komura, Shigeyuki, E-mail: komura@tmu.ac.jp [Department of Chemistry, Graduate School of Science and Engineering, Tokyo Metropolitan University, Tokyo 192-0397 (Japan); Kavli Institute for Theoretical Physics China, CAS, Beijing 100190 (China); Andelman, David, E-mail: andelman@post.tau.ac.il [Raymond and Beverly Sackler School of Physics and Astronomy, Tel Aviv University, Ramat Aviv, Tel Aviv 69978 (Israel); Kavli Institute for Theoretical Physics China, CAS, Beijing 100190 (China)

2015-12-28

Motivated by the experimental study of Tayebi et al. [Nat. Mater. 11, 1074 (2012)] on phase separation of stacked multi-component lipid bilayers, we propose a model composed of stacked two-dimensional Ising spins. We study both its static and dynamical features using Monte Carlo simulations with Kawasaki spin exchange dynamics that conserves the order parameter. We show that at thermodynamical equilibrium, due to strong inter-layer correlations, the system forms a continuous columnar structure for any finite interaction across adjacent layers. Furthermore, the phase separation shows a faster dynamics as the inter-layer interaction is increased. This temporal behavior is mainly due to an effective deeper temperature quench because of the larger value of the critical temperature, T{sub c}, for larger inter-layer interaction. When the temperature ratio, T/T{sub c}, is kept fixed, the temporal growth exponent does not increase and even slightly decreases as a function of the increased inter-layer interaction.

Effect of stimulated phase separation on properties of blue, green and monolithic white LEDs

Energy Technology Data Exchange (ETDEWEB)

Tsatsulnikov, A.F.; Lundin, W.V.; Sakharov, A.V.; Zavarin, E.E.; Nikolaev, A.E.; Sizov, V.S. [Ioffe Physical-Technical Institute, Russian Academy of Sciences, Politekhnicheskaya Str. 26, 194021 St. Petersburg (Russian Federation); Usov, S.O.; Zakgeim, A.L.; Mizerov, M.N. [Submicron Heterostructures for Microelectronics Research and Engineering Center, Russian Academy of Sciences, Politekhnicheskaya Str. 26, 194021 St. Petersburg (Russian Federation); Cherkashin, N.A.; Hytch, M. [CEMES-CNRS, Universite de Toulouse, Toulouse (France)

2012-03-15

Different methods of stimulation of phase separation in an InGaN QWs by technological methods and by design of structure were investigated. Effect of admixing of hydrogen during growth interruptions (GIs) after deposition of the InGaN QWs on their structural and optical properties and properties of InGaN-based LEDs was investigated. Effect of growth pressure on the phase separation was investigated and formation of separate InGaN islands at increase in growth pressure was revealed. It was shown that the phase separation is stimulated in composite InAlN/GaN/InGaN heterostructures and formation of well isolated InGaN islands was observed. Effect of the phase separation on the properties of the blue and deep green LEDs was investigated and strong changes in the spectral position and current dependence of the quantum efficiency were revealed. It was shown that formation of the island due to the phase separation allows control position and width of the emission line and maximum in current dependence of the quantum efficiency. Monolithic white LEDs are containing in active region blue and green InGaN QWs grown with applying of the GIs and emitting in spectral range from 440 nm to 560 nm were studied. Monolithic white LEDs having optimal design of active region demonstrate CCT in the range of 9000-12000 K and maximal external quantum efficiency up to 14 lm/W. (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Evaluation of phase separator number in hydrodesulfurization (HDS) unit

Science.gov (United States)

Jayanti, A. D.; Indarto, A.

2016-11-01

The removal process of acid gases such as H2S in natural gas processing industry is required in order to meet sales gas specification. Hydrodesulfurization (HDS)is one of the processes in the refinery that is dedicated to reduce sulphur.InHDS unit, phase separator plays important role to remove H2S from hydrocarbons, operated at a certain pressure and temperature. Optimization of the number of separator performed on the system is then evaluated to understand the performance and economics. From the evaluation, it shows that all systems were able to meet the specifications of H2S in the desired product. However, one separator system resulted the highest capital and operational costs. The process of H2S removal with two separator systems showed the best performance in terms of both energy efficiency with the lowest capital and operating cost. The two separator system is then recommended as a reference in the HDS unit to process the removal of H2S from natural gas.

Investigation of phase separated polyimide blend films containing boron nitride using FTIR imaging

Science.gov (United States)

Chae, Boknam; Hong, Deok Gi; Jung, Young Mee; Won, Jong Chan; Lee, Seung Woo

2018-04-01

Immiscible aromatic polyimide (PI) blend films and a PI blend film incorporated with thermally conductive boron nitride (BN) were prepared, and their phase separation behaviors were examined by optical microscopy and FTIR imaging. The 2,2‧-bis(trifluoromethyl)benzidine (TFMB)-containing and 4,4‧-thiodianiline (TDA)-containing aromatic PI blend films and a PI blend/BN composite film show two clearly separated regions; one region is the TFMB-rich phase, and the other region is the TDA-rich phase. The introduction of BN induces morphological changes in the immiscible aromatic PI blend film without altering the composition of either domain. In particular, the BN is selectively incorporated into the TDA-rich phase in this study.

Synergistic extraction of transition metal cations from aqueous media by two separated organic phases

International Nuclear Information System (INIS)

Goldberg, I.

1991-12-01

We have therefore initiated novel approaches to the study of the mechanism of the synergistic extraction of metal ions by means of two separated organic phases, which are brought in contact with the same aqueous phase. The present work is concerned with the extraction of transition metals and actinides ions from nitric acid by chelating agents e.g., HTTA thenoyltrifluoroacetone in a diluent - the first organic phase, and by natural donor, e.g., TBP, tri-butyl phosphate in a diluent the second organic phase. The adduct formation was studied by means of spectrochemical and radiochemical methods. In the first approach the aqueous phase was attacked with both organic phases simultanously (the static or parallel extraction). In this method organic phase are separated one from the other. It was shown that even in the absence of mixing, synergism is observed under this experimental conditions. The results indicate, that adduct formation occurs in both organic phases. Nevertheless the enhanchment of extraction in the TBP phase is by far greater than that in the HTTA containing phase. This approach has one disadvatage, viz., the experiments are very time consuming, a typical experiment requiring over 10 days. In order to overcome this difficulty, the following experiments were carried out: the aqueous phase were first shaken with diluent containing an anionic ligand and the phases were allowed to separate. Then the aqueous solution were shaken with diluent containing a netural donor and the phase again were allowed to separate. The concentration of the metal ions in all the phases were determined. The experiments were repeated with an other diluent replacing the first diluent in one or both organic phases. In this way eight sequences of experiments were carried out for each concentration set chosen. The results thus point out that this experimental approach open new possibilities to investigate the mechanism and the kinetics of synergistic extraction processes. (author) the

Effect of Difference in Fatty Acid Chain Lengths of Medium- Chain Lipids on Lipid/Surfactant/Water Phase Diagrams and Drug Solubility

Directory of Open Access Journals (Sweden)

Hetal N. Prajapati

2011-09-01

Full Text Available Lipids consisting of medium chain fatty acids are commonly used in the development of lipid-based selfemulsifying and self-microemulsifying drug delivery systems. However, no systematic approach to selecting one lipid over another has been reported in the literature. In this study, propylene glycol (PG monoester (PG monocaprylate, Capmul PG-8® and PG diester (PG dicaprylocaprate, Captex 200P® of C8-fatty acids were compared with PG monoester (PG monolaurate, Capmul PG-12® and PG diester (PG dilaurate, Capmul PG-2L® of C12-fatty acids with respect to their phase diagrams, and especially for their ability to form microemulsions in the presence of a common surfactant, Cremophor EL®, and water. The solubility of two model drugs, danazol and probucol, in the lipids and lipid/surfactant mixtures were also compared. The effect of the chain length of medium-chain fatty acids (C8 versus C12 on the phase diagrams of the lipids was minimal. Both shorter and longer chain lipids formed essentially similar microemulsion and emulsion regions in the presence of Cremophor EL® and water, although the C12-fatty acid esters formed larger gel regions in the phase diagrams than the C8-fatty acid esters. When monoesters were mixed with their respective diesters at 1:1 ratios, larger microemulsion regions with lower lipid particle sizes were observed compared to those obtained with individual lipids alone. While the solubility of both danazol and probucol increased greatly in all lipids studied, compared to their aqueous solubility, the solubility in C12-fatty acid esters was found to be lower than in C8-fatty acid esters when the lipids were used alone. This difference in solubility due to the difference in fatty acid chain length, practically disappeared when the lipids were combined with the surfactant.

The second workshop on phase separation with ordering

International Nuclear Information System (INIS)

Osamura, K.; Furusaka, M.

1993-04-01

The second workshop on phase separation with ordering was held at the seminar room of Booster, National Laboratory for High Energy Physics, KEK, Tsukuba, in March 16-17, 1992. 31 participants attended this meeting. The structure and its dynamical change were discussed mainly in the experimental viewpoint, and the theories have been developed and the results of simulation were reported. (J.P.N.) 115 refs

Preparation and Characterization of Membranes Formed by Nonsolvent Induced Phase Separation: A Review

KAUST Repository

Guillen, Gregory R.

2011-04-06

The methods and mechanisms of nonsolvent induced phase separation have been studied for more than fifty years. Today, phase inversion membranes are widely used in numerous chemical industries, biotechnology, and environmental separation processes. The body of knowledge has grown exponentially in the past fifty years, which suggests the need for a critical review of the literature. Here we present a review of nonsolvent induced phase separation membrane preparation and characterization for many commonly used membrane polymers. The key factors in membrane preparation discussed include the solvent type, polymer type and concentration, nonsolvent system type and composition, additives to the polymer solution, and film casting conditions. A brief introduction to membrane characterization is also given, which includes membrane porosity and pore size distribution characterization, membrane physical and chemical properties characterization, and thermodynamic and kinetic evaluation of the phase inversion process. One aim of this review is to lay out the basics for selecting polymer solvent nonsolvent systems with appropriate film casting conditions to produce membranes with the desired performance, morphology, and stability, and to choose the proper way to characterize these properties of nonsolvent induced phase inversion membranes. © 2011 American Chemical Society.

Phase separation and d-wave superconductivity induced by extended electron-exciton interaction

Energy Technology Data Exchange (ETDEWEB)

Cheng Ming [Department of Physics and Texas Center for Superconductivity, University of Houston, 4800 Calhoun Road, Houston, Texas 77204 (United States)], E-mail: cheng896@hotmail.com; Su Wupei [Department of Physics and Texas Center for Superconductivity, University of Houston, 4800 Calhoun Road, Houston, Texas 77204 (United States)

2008-12-15

Using an auxiliary-field quantum Monte Carlo (AFQMC) method, we have studied a two-dimensional tight-binding model in which the conduction electrons can polarize an adjacent layer of molecules through electron-electron repulsion. Calculated average conduction electron density as a function of chemical potential exhibits a clear break characteristic of phase separation. Compared to the noninteracting system, the d-wave pair-field correlation function shows significant enhancement. The simultaneous presence of phase separation and d-wave superconductivity suggests that an effective extended pairing force is induced by the electron-exciton coupling.

Phase separation and d-wave superconductivity induced by extended electron-exciton interaction

International Nuclear Information System (INIS)

Cheng Ming; Su Wupei

2008-01-01

Using an auxiliary-field quantum Monte Carlo (AFQMC) method, we have studied a two-dimensional tight-binding model in which the conduction electrons can polarize an adjacent layer of molecules through electron-electron repulsion. Calculated average conduction electron density as a function of chemical potential exhibits a clear break characteristic of phase separation. Compared to the noninteracting system, the d-wave pair-field correlation function shows significant enhancement. The simultaneous presence of phase separation and d-wave superconductivity suggests that an effective extended pairing force is induced by the electron-exciton coupling

Separable pairing force for relativistic quasiparticle random-phase approximation

International Nuclear Information System (INIS)

Tian Yuan; Ma Zhongyu; Ring, Peter

2009-01-01

We have introduced a separable pairing force, which was adjusted to reproduce the pairing properties of the Gogny force in nuclear matter. This separable pairing force is able to describe in relativistic Hartree-Bogoliubov (RHB) calculations the pairing properties in the ground state of finite nuclei on almost the same footing as the original Gogny interaction. In this work we investigate excited states using the Relativistic Quasiparticle Random-Phase Approximation (RQRPA) with the same separable pairing force. For consistency the Goldstone modes and the convergence with various cutoff parameters in this version of RQRPA are studied. The first excited 2 + states for the chain of Sn isotopes with Z=50 and the chain of isotones with N=82 isotones are calculated in RQRPA together with the 3 - states of Sn isotopes. By comparing our results with experimental data and with the results of the original Gogny force we find that this simple separable pairing interaction is very successful in depicting the pairing properties of vibrational excitations.

Precipitation phase separation schemes in the Naqu River basin, eastern Tibetan plateau

Science.gov (United States)

Liu, Shaohua; Yan, Denghua; Qin, Tianling; Weng, Baisha; Lu, Yajing; Dong, Guoqiang; Gong, Boya

2018-01-01

Precipitation phase has a profound influence on the hydrological processes in the Naqu River basin, eastern Tibetan plateau. However, there are only six meteorological stations with precipitation phase (rainfall/snowfall/sleet) before 1979 within and around the basin. In order to separate snowfall from precipitation, a new separation scheme with S-shaped curve of snowfall proportion as an exponential function of daily mean temperature was developed. The determinations of critical temperatures in the single/two temperature threshold (STT/TTT2) methods were explored accordingly, and the temperature corresponding to the 50 % snowfall proportion (SP50 temperature) is an efficiently critical temperature for the STT, and two critical temperatures in TTT2 can be determined based on the exponential function and SP50 temperature. Then, different separation schemes were evaluated in separating snowfall from precipitation in the Naqu River basin. The results show that the S-shaped curve methods outperform other separation schemes. Although the STT and TTT2 slightly underestimate and overestimate the snowfall when the temperature is higher and colder than SP50 temperature respectively, the monthly and annual separation snowfalls are generally consistent with the observed snowfalls. On the whole, S-shaped curve methods, STT, and TTT2 perform well in separating snowfall from precipitation with the Pearson correlation coefficient of annual separation snowfall above 0.8 and provide possible approaches to separate the snowfall from precipitation for hydrological modelling.

Fabrication of PVDF-based blend membrane with a thin hydrophilic deposition layer and a network structure supporting layer via the thermally induced phase separation followed by non-solvent induced phase separation process

Science.gov (United States)

Wu, Zhiguo; Cui, Zhenyu; Li, Tianyu; Qin, Shuhao; He, Benqiao; Han, Na; Li, Jianxin

2017-10-01

A simple strategy of thermally induced phase separation followed by non-solvent induced phase separation (TIPS-NIPS) is reported to fabricate poly (vinylidene fluoride) (PVDF)-based blend membrane. The dissolved poly (styrene-co-maleic anhydride) (SMA) in diluent prevents the crystallization of PVDF during the cooling process and deposites on the established PVDF matrix in the later extraction. Compared with traditional coating technique, this one-step TIPS-NIPS method can not only fabricate a supporting layer with an interconnected network structure even via solid-liquid phase separation of TIPS, but also form a uniform SMA skin layer approximately as thin as 200 nm via surface deposition of NIPS. Besides the better hydrophilicity, what's interesting is that the BSA rejection ratio increases from 48% to 94% with the increase of SMA, which indicates that the separation performance has improved. This strategy can be conveniently extended to the creation of firmly thin layer, surface functionalization and structure controllability of the membrane.

Effect of the Hartmann number on phase separation controlled by magnetic field for binary mixture system with large component ratio

Science.gov (United States)

Heping, Wang; Xiaoguang, Li; Duyang, Zang; Rui, Hu; Xingguo, Geng

2017-11-01

This paper presents an exploration for phase separation in a magnetic field using a coupled lattice Boltzmann method (LBM) with magnetohydrodynamics (MHD). The left vertical wall was kept at a constant magnetic field. Simulations were conducted by the strong magnetic field to enhance phase separation and increase the size of separated phases. The focus was on the effect of magnetic intensity by defining the Hartmann number (Ha) on the phase separation properties. The numerical investigation was carried out for different governing parameters, namely Ha and the component ratio of the mixed liquid. The effective morphological evolutions of phase separation in different magnetic fields were demonstrated. The patterns showed that the slant elliptical phases were created by increasing Ha, due to the formation and increase of magnetic torque and force. The dataset was rearranged for growth kinetics of magnetic phase separation in a plot by spherically averaged structure factor and the ratio of separated phases and total system. The results indicate that the increase in Ha can increase the average size of separated phases and accelerate the spinodal decomposition and domain growth stages. Specially for the larger component ratio of mixed phases, the separation degree was also significantly improved by increasing magnetic intensity. These numerical results provide guidance for setting the optimum condition for the phase separation induced by magnetic field.

Lower critical solution temperature (LCST) phase separation of glycol ethers for forward osmotic control.

Science.gov (United States)

Nakayama, Daichi; Mok, Yeongbong; Noh, Minwoo; Park, Jeongseon; Kang, Sunyoung; Lee, Yan

2014-03-21

Lower critical solution temperature (LCST) phase transition of glycol ether (GE)-water mixtures induces an abrupt change in osmotic pressure driven by a mild temperature change. The temperature-controlled osmotic change was applied for the forward osmosis (FO) desalination. Among three GEs evaluated, di(ethylene glycol) n-hexyl ether (DEH) was selected as a potential FO draw solute. A DEH-water mixture with a high osmotic pressure could draw fresh water from a high-salt feed solution such as seawater through a semipermeable membrane at around 10 °C. The water-drawn DEH-water mixture was phase-separated into a water-rich phase and a DEH-rich phase at around 30 °C. The water-rich phase with a much reduced osmotic pressure released water into a low-salt solution, and the DEH-rich phase was recovered into the initial DEH-water mixture. The phase separation behaviour, the residual GE concentration in the water-rich phase, the osmotic pressure of the DEH-water mixture, and the osmotic flux between the DEH-water mixture and salt solutions were carefully analysed for FO desalination. The liquid-liquid phase separation of the GE-water mixture driven by the mild temperature change between 10 °C and 30 °C is very attractive for the development of an ideal draw solute for future practical FO desalination.

Solubility of hydrogen in bio-oil compounds

International Nuclear Information System (INIS)

Qureshi, Muhammad Saad; Touronen, Jouni; Uusi-Kyyny, Petri; Richon, Dominique; Alopaeus, Ville

2016-01-01

Highlights: • Solubility of Hydrogen was measured in bio-oil compounds in the at temperatures from 342 to 473 K and pressures up to 16 MPa. • Phase equilibrium data were acquired using a visualization enabled continuous flow synthetic apparatus. • The measured solubility is modeled with Peng-Robinson EoS. - Abstract: The knowledge of accurate hydrogen solubility values in bio-oil compounds is essential for the design and optimization of hydroprocesses relevant to biofuel industry. This work reports the solubility of hydrogen in three industrially relevant bio-oil compounds (allyl alcohol, furan, and eugenol) at temperatures from 342 to 473 K and pressures up to 16 MPa. Phase equilibrium data were acquired using a continuous flow synthetic method. The method is based on the visual observation of the bubble point using a high resolution camera. The measured solubility is modeled with Peng-Robinson EoS with classical van der Waals one fluid mixing rules.

Sub-1min separation in sequential injection chromatography for determination of synthetic water-soluble dyes in pharmaceutical formulation.

Science.gov (United States)

Davletbaeva, Polina; Chocholouš, Petr; Bulatov, Andrey; Šatínský, Dalibor; Solich, Petr

2017-09-05

Sequential Injection Chromatography (SIC) evolved from fast and automated non-separation Sequential Injection Analysis (SIA) into chromatographic separation method for multi-element analysis. However, the speed of the measurement (sample throughput) is due to chromatography significantly reduced. In this paper, a sub-1min separation using medium polar cyano monolithic column (5mm×4.6mm) resulted in fast and green separation with sample throughput comparable with non-separation flow methods The separation of three synthetic water-soluble dyes (sunset yellow FCF, carmoisine and green S) was in a gradient elution mode (0.02% ammonium acetate, pH 6.7 - water) with flow rate of 3.0mLmin -1 corresponding with sample throughput of 30h -1 . Spectrophotometric detection wavelengths were set to 480, 516 and 630nm and 10Hz data collection rate. The performance of the separation was described and discussed (peak capacities 3.48-7.67, peak symmetries 1.72-1.84 and resolutions 1.42-1.88). The method was represented by validation parameters: LODs of 0.15-0.35mgL -1 , LOQs of 0.50-1.25mgL -1 , calibration ranges 0.50-150.00mgL -1 (r>0.998) and repeatability at 10.0mgL -1 of RSD≤0.98% (n=6). The method was used for determination of the dyes in "forest berries" colored pharmaceutical cough-cold formulation. The sample matrix - pharmaceuticals and excipients were not interfering with vis determination because of no retention in the separation column and colorless nature. The results proved the concept of fast and green chromatography approach using very short medium polar monolithic column in SIC. Copyright © 2017 Elsevier B.V. All rights reserved.

Polymeric microsieves via phase separation microfabrication: Process and design optimization

NARCIS (Netherlands)

Bikel, M.; Culfaz, P.Z.; Bolhuis-Versteeg, Lydia A.M.; Perez, J. Garduno; Lammertink, Rob G.H.; Wessling, Matthias

2010-01-01

Phase separation microfabrication (PSμF) is a fabrication method that allows the preparation of membranes having micropattern surface topologies. PSμF has been successfully used for manufacturing polymeric microsieves. The technique benefits from the vertical shrinkage of polymer solutions to ensure

The solubilities and solubility products of zirconium hydroxide and oxide after aging at 278, 313, and 333 K

Energy Technology Data Exchange (ETDEWEB)

Kobayashi, Taishi; Uemura, Takuya; Sasaki, Takayuki; Takagi, Ikuji [Kyoto Univ. (Japan). Dept. of Nuclear Engineering; Moriyama, Hirotake [Kyoto Univ. (Japan). Research Reactor Inst.

2016-07-01

The solubilities of zirconium hydroxide and oxide after aging at 278, 313, and 333 K were measured at 278, 298, 313, and 333 K in the pH{sub c} range of 0.3-7 in a 0.5 M ionic strength solution of NaClO{sub 4} and HClO{sub 4}. Size distributions of the colloidal species were investigated by ultrafiltration using membranes with different pore sizes, and the solid phases were examined by X-ray diffraction. The apparent solubility of zirconium amorphous hydroxide (Zr(OH){sub 4}(am)), prepared by the oversaturation method, decreased with increasing aging temperature (T{sub a}), and the size distributions obtained after aging at elevated temperatures indicated the growth of the colloidal species. We, therefore, suggested that agglomeration of the colloidal species and dehydration and crystallization of Zr(OH){sub 4}(am) as the solubility-limiting solid phase occurred over the course of aging at elevated temperatures. For sample solutions of the crystalline oxide (ZrO{sub 2}(cr)), the aging temperature had no significant effect on the solubility, but the solubility data at lower temperatures were found to be slightly higher than those at higher temperatures, implying a small fraction of the amorphous components. In the analysis of different solid phases (Zr(OH){sub 4}(s,T{sub a}), T{sub a} = 278, 313, and 333 K) depending on the aging temperatures, the solubility products (K{sub sp}, T{sub a}) were determined at different measurement temperatures, and the enthalpy change (Δ{sub r}H {sup circle}) for Zr{sup 4+} 4OH{sup -} <=> Zr(OH){sub 4}(s,T{sub a}) was calculated using the van't Hoff equation. The solid-phase-transformation process at elevated temperatures was also analyzed based on the obtained K{sub sp}, T{sub a} and Δ{sub r}H {sup circle} values.

Controlled Topological Transitions in Thin-Film Phase Separation

KAUST Repository

Hennessy, Matthew G.; Burlakov, Victor M.; Goriely, Alain; Wagner, Barbara; Mü nch, Andreas

2015-01-01

© 2015 Society for Industrial and Applied Mathematics. In this paper the evolution of a binary mixture in a thin-film geometry with a wall at the top and bottom is considered. By bringing the mixture into its miscibility gap so that no spinodal decomposition occurs in the bulk, a slight energetic bias of the walls toward each one of the constituents ensures the nucleation of thin boundary layers that grow until the constituents have moved into one of the two layers. These layers are separated by an interfacial region where the composition changes rapidly. Conditions that ensure the separation into two layers with a thin interfacial region are investigated based on a phase-field model. Using matched asymptotic expansions a corresponding sharp-interface problem for the location of the interface is established. It is then argued that this newly created two-layer system is not at its energetic minimum but destabilizes into a controlled self-replicating pattern of trapezoidal vertical stripes by minimizing the interfacial energy between the phases while conserving their area. A quantitative analysis of this mechanism is carried out via a thin-film model for the free interfaces, which is derived asymptotically from the sharp-interface model.

Molecular dynamics study of salt–solution interface: Solubility and surface charge of salt in water

International Nuclear Information System (INIS)

Kobayashi, Kazuya; Liang, Yunfeng; Matsuoka, Toshifumi; Sakka, Tetsuo

2014-01-01

The NaCl salt–solution interface often serves as an example of an uncharged surface. However, recent laser-Doppler electrophoresis has shown some evidence that the NaCl crystal is positively charged in its saturated solution. Using molecular dynamics (MD) simulations, we have investigated the NaCl salt–solution interface system, and calculated the solubility of the salt using the direct method and free energy calculations, which are kinetic and thermodynamic approaches, respectively. The direct method calculation uses a salt–solution combined system. When the system is equilibrated, the concentration in the solution area is the solubility. In the free energy calculation, we separately calculate the chemical potential of NaCl in two systems, the solid and the solution, using thermodynamic integration with MD simulations. When the chemical potential of NaCl in the solution phase is equal to the chemical potential of the solid phase, the concentration of the solution system is the solubility. The advantage of using two different methods is that the computational methods can be mutually verified. We found that a relatively good estimate of the solubility of the system can be obtained through comparison of the two methods. Furthermore, we found using microsecond time-scale MD simulations that the positively charged NaCl surface was induced by a combination of a sodium-rich surface and the orientation of the interfacial water molecules

Study on REE bound water-soluble polysaccharides in plant

International Nuclear Information System (INIS)

Wang Yuqi; Guo Fanqing; Xu Lei; Chen Hongmin; Sun Jingxin; Cao Guoyin

1999-01-01

The binding of REE with water-soluble polysaccharides (PSs) in leaves of fern Dicranopteris Dichotoma (DD) has been studied by molecular activation analysis. The cold-water-soluble and hot-water-soluble PSs in leaves of DD were obtained by using biochemical separation techniques. The PSs of non-deproteinization and deproteinization, were separated on Sephadex G-200 gel permeation chromatography. The absorption curves of elution for the PSs were obtained by colorimetry, and the proteins were detected using Coomassic brilliant G-250. Eight REEs (La, Ce, Nd, Sm, Eu, Tb, Yb and Lu) in these PSs were determined by instrumental neutron activation analysis. The results obtained show that the REEs are bound firmly with the water-soluble PSs in the plant. A measurement demonstrates that the PSs bound with REEs are mainly of smaller molecular weight (10,000 to 20,000 Dalton)

Are separate-phase thermal-hydraulic models better than mixture-fluid approaches? It depends. Rather not

International Nuclear Information System (INIS)

Hoeld, A.

2004-01-01

The thermal-hydraulic theory of single- and especially two-phase flow systems used for plant transient analysis is dominated by separate-phase models. The corresponding mostly very comprehensive codes (TRAC, RELAP, CATHARE, ATHLET etc.) are looked as to be by far more efficient than a 3 eq. mixture-fluid approach and code also if they show deficiencies in describing flow situations within inner loops as for example the distribution into parallel channels (and thus the simulation of 3D thermal-hydraulic phenomena). This may be justified if comparing them to the very simple 'homogeneous equilibrium models (HEM)', but not if looking to the more refined non-homogeneous 'separate-region' mixture-fluid approaches based on appropriate drift-flux correlation packages which can have, on the contrary, enormous advantages with respect to such separate-phase models. Especially if comparing the basic (and starting) eqs. of such theoretical models of both types the differences are remarkable. Single-phase and mixture-fluid models start from genuine conservation eqs. for mass, energy and momentum, demanding (in case of two-phase flow) additionally an adequate drift flux package (in order to get a relation for a fourth independent variable), a heat transfer coefficients package (over the whole range of the possible fields of application) and correlations for single- and two-phase friction. The other types of models are looking at each phase separately with corresponding 'field' eqs. for each phase, connected by exchange (=closure) terms which substitute the classical constitutive packages for drift, heat transfer and friction. That the drift-flux, heat transfer into a coolant channel and friction along a wall and between the phases is described better by a separate-phase approach is at least doubtful. The corresponding mixture-fluid correlations are based over a wide range on a treasure of experience and measurements, their pseudo-stationary treatment can (due to their small time

[Advances of poly (ionic liquid) materials in separation science].

Science.gov (United States)

Liu, Cuicui; Guo, Ting; Su, Rina; Gu, Yuchen; Deng, Qiliang

2015-11-01

Ionic liquids, as novel ionization reagents, possess beneficial characteristics including good solubility, conductivity, thermal stability, biocompatibility, low volatility and non-flammability. Ionic liquids are attracting a mass of attention of analytical chemists. Poly (ionic liquid) materials have common performances of ionic liquids and polymers, and have been successfully applied in separation science area. In this paper, we discuss the interaction mechanisms between the poly(ionic liquid) materials and analytes including hydrophobic/hydrophilic interactions, hydrogen bond, ion exchange, π-π stacking and electrostatic interactions, and summarize the application advances of the poly(ionic liquid) materials in solid phase extraction, chromatographic separation and capillary electrophoresis. At last, we describe the future prospect of poly(ionic liquid) materials.

[Separation and determination of eight plant hormones by reversed-phase high performance liquid chromatography].

Science.gov (United States)

Fang, N; Hou, S; Shao, X; He, Y; Zhao, G

1998-09-01

In this paper, reversed-phase high performance liquid chromatographic technique was used for the separation and determination of eight plant hormones. Methanol-water-acetic acid system was chosen as the mobile phase. The effects of different separation conditions, such as the methanol and acetic acid concentrations in mobile phase, on the retention behaviours of eight plant hormones in this system were studied. The general trends in retention behaviours could be correlated to the methanol concentration in mobile phase. The experimental results showed that the optimum separation was achieved with following gradient elution condition: 0-3 minutes, 70% (water percentage in mobile phase), 3-13 minutes, 70%-20%, 13-48 minutes, 20%. Benzene was added to be as the internal standard. Under this experimental condition, the eight plant hormones could be separated completely and detected quantitatively at 260 nm within 16 minutes. The calibration curves for the eight compounds gave linearity over a wide range. The correlation coefficients of each components were r(ZT) = 0.9971, r(GAs) = 0.9999, r(K) = 0.9997, r(BA) = 0.9995, r(IAA) = 0.9998, r(IPA) = 0.9982, r(IBA) = 0.9995 and r(NAA) = 0.9995. The method is rapid, simple and efficient. It is a suitable method for the accurate determination of gibberellic acid (GA) and alpha-naphthaleneacetic acid (alpha-NAA) in products for agricultural use.

Silk fibroin gelation via non-solvent induced phase separation

Czech Academy of Sciences Publication Activity Database

Kasoju, Naresh; Hawkins, N.; Pop-Georgievski, Ognen; Kubies, Dana; Vollrath, F.

2016-01-01

Roč. 4, č. 3 (2016), s. 460-473 ISSN 2047-4830 R&D Projects: GA MŠk(CZ) EE2.3.30.0029; GA MŠk(CZ) ED1.1.00/02.0109 Institutional support: RVO:61389013 Keywords : silk fibroin * non-solvent induced phase separation * desolvation Subject RIV: CE - Biochemistry Impact factor: 4.210, year: 2016

Phase separation temperatures of a liquid mixture: Dynamic light scattering technique

International Nuclear Information System (INIS)

Dangudom, K.; Wongtawatnugool, C.; Lacharojana, S.

2010-01-01

Light scattering intensity measurements and photon correlation spectroscopy (PCS) techniques were employed in an investigation of liquid-liquid phase separation behaviour of a mixture of cyclohexane and methanol at seven different compositions. It was found that, except for one composition (29% methanol), the temperature at which the scattering intensity was a maximum did not coincide with the one where the diffusion coefficient was a minimum, as would be for the case of a vapour-liquid system. The difference may be explained in terms of the local density fluctuation and the random walk problem responsible for the peak intensity and the minimum in the diffusion coefficient, respectively. The definition of phase separation temperature, as determined from diffusion process, was also proposed in this work.

The solubility-permeability interplay and its implications in formulation design and development for poorly soluble drugs.

Science.gov (United States)

Dahan, Arik; Miller, Jonathan M

2012-06-01

While each of the two key parameters of oral drug absorption, the solubility and the permeability, has been comprehensively studied separately, the relationship and interplay between the two have been largely ignored. For instance, when formulating a low-solubility drug using various solubilization techniques: what are we doing to the apparent permeability when we increase the solubility? Permeability is equal to the drug's diffusion coefficient through the membrane times the membrane/aqueous partition coefficient divided by the membrane thickness. The direct correlation between the intestinal permeability and the membrane/aqueous partitioning, which in turn is dependent on the drug's apparent solubility in the GI milieu, suggests that the solubility and the permeability are closely associated, exhibiting a certain interplay between them, and the current view of treating the one irrespectively of the other may not be sufficient. In this paper, we describe the research that has been done thus far, and present new data, to shed light on this solubility-permeability interplay. It has been shown that decreased apparent permeability accompanies the solubility increase when using different solubilization methods. Overall, the weight of the evidence indicates that the solubility-permeability interplay cannot be ignored when using solubility-enabling formulations; looking solely at the solubility enhancement that the formulation enables may be misleading with regards to predicting the resulting absorption, and hence, the solubility-permeability interplay must be taken into account to strike the optimal solubility-permeability balance, in order to maximize the overall absorption.

Solid phase radioimmunoassays

International Nuclear Information System (INIS)

Wide, L.

1977-01-01

Solid phase coupled antibodies were introduced to facilitate the separation of bound and free labelled ligand in the competitive inhibition radioimmunoassay. Originally, the solid matrix used was in the form of small particles and since then a number of different matrices have been used such as very fine powder particles, gels, paper and plastic discs, magnetic particles and the inside surface of plastic tubes. The coupling of antibodies may be that of a covalent chemical binding, a strong physical adsorbtion, or an immunological binding to a solid phase coupled antigen. New principles of radioimmunoassay such as the solid phase sandwich techniques and the immunoradiometric assay were developped from the use of solid phase coupled antigens and antibodies. The solid phase sandwich techniques are reagent excess methods with a very wide applicability. Several of the different variants of solid phase techniques are suitable for automation. Advantages and disadvantages of solid phase radioimmunoassays when compared with those using soluble reagents are discussed. (orig.) [de

Methods of calculating engineering parameters for gas separations

Science.gov (United States)

Lawson, D. D.

1980-01-01

A group additivity method has been generated which makes it possible to estimate, from the structural formulas alone, the energy of vaporization and the molar volume at 25 C of many nonpolar organic liquids. From these two parameters and appropriate thermodynamic relationships it is then possible to predict the vapor pressure of the liquid phase and the solubility of various gases in nonpolar organic liquids. The data are then used to evaluate organic and some inorganic liquids for use in gas separation stages or as heat exchange fluids in prospective thermochemical cycles for hydrogen production.

Liquid-liquid phase separation in aerosol particles: Imaging at the Nanometer Scale

Energy Technology Data Exchange (ETDEWEB)

O' Brien, Rachel; Wang, Bingbing; Kelly, Stephen T.; Lundt, Nils; You, Yuan; Bertram, Allan K.; Leone, Stephen R.; Laskin, Alexander; Gilles, Mary K.

2015-04-21

Atmospheric aerosols can undergo phase transitions including liquid-liquid phase separation (LLPS) while responding to changes in the ambient relative humidity (RH). Here, we report results of chemical imaging experiments using environmental scanning electron microscopy (ESEM) and scanning transmission x-ray microscopy (STXM) to investigate the LLPS of micron sized particles undergoing a full hydration-dehydration cycle. Internally mixed particles composed of ammonium sulfate (AS) and either: limonene secondary organic carbon (LSOC), a, 4-dihydroxy-3-methoxybenzeneaceticacid (HMMA), or polyethylene glycol (PEG-400) were studied. Events of LLPS with apparent core-shell particle morphology were observed for all samples with both techniques. Chemical imaging with STXM showed that both LSOC/AS and HMMA/AS particles were never homogeneously mixed for all measured RH’s above the deliquescence point and that the majority of the organic component was located in the shell. The shell composition was estimated as 65:35 organic: inorganic in LSOC/AS and as 50:50 organic: inorganic for HMMA/AS. PEG-400/AS particles showed fully homogeneous mixtures at high RH and phase separated below 89-92% RH with an estimated 50:50% organic to inorganic mix in the shell. These two chemical imaging techniques are well suited for in-situ analysis of the hygroscopic behavior, phase separation, and surface composition of collected ambient aerosol particles.

The effects of disordered structure on the solubility and dissolution rates of some hydrophilic, sparingly soluble drugs.

Science.gov (United States)

Mosharraf, M; Sebhatu, T; Nyström, C

1999-01-15

The effects of experimental design on the apparent solubility of two sparingly soluble hydrophilic compounds (barium sulphate and calcium carbonate) were studied in this paper. The apparent solubility appeared to be primarily dependent on the amount of solute added to the solvent in each experiment, increasing with increased amounts. This effect seems to be due to the existence of a peripheral disordered layer. However physico-chemical methods used in the present study were not able to unambiguously verify the existence of any disorder in the solid state structure of the drugs. At higher proportions of solute to solvent, the solubility reached a plateau corresponding to the solubility of the disordered or amorphous molecular form of the material. Milling the powders caused the plateau to be reached at lower proportions of solute to solvent, since this further disordered the surface of the drug particles. It was also found that the apparent solubility of the drugs tested decreased after storage at high relative humidities. A model for describing the effects of a disordered surface layer of varying thickness and continuity on the solubility of a substance is presented. This model may be used as a method for detection of minute amount of disorder, where no other technique is capable of detecting the disordered structure. It is suggested that recrystallisation of the material occurs via slow solid-state transition at the surface of the drug particle; this would slowly reduce the apparent solubility of the substance at the plateau level to the thermodynamically stable value. A biphasic dissolution rate profile was obtained. The solubility of the disordered surface of the particles appeared to be the rate-determining factor during the initial dissolution phase, while the solubility of the crystalline core was the rate-determining factor during the final slower phase.

Vacancy-mediated fcc/bcc phase separation in Fe1 -xNix ultrathin films

Science.gov (United States)

Menteş, T. O.; Stojić, N.; Vescovo, E.; Ablett, J. M.; Niño, M. A.; Locatelli, A.

2016-08-01

The phase separation occurring in Fe-Ni thin films near the Invar composition is studied by using high-resolution spectromicroscopy techniques and density functional theory calculations. Annealed at temperatures around 300 ∘C ,Fe0.70Ni0.30 films on W(110) break into micron-sized bcc and fcc domains with compositions in agreement with the bulk Fe-Ni phase diagram. Ni is found to be the diffusing species in forming the chemical heterogeneity. The experimentally determined energy barrier of 1.59 ±0.09 eV is identified as the vacancy formation energy via density functional theory calculations. Thus, the principal role of the surface in the phase separation process is attributed to vacancy creation without interstitials.

Polymide gas separation membranes

Science.gov (United States)

Ding, Yong; Bikson, Benjamin; Nelson, Joyce Katz

2004-09-14

Soluble polyamic acid salt (PAAS) precursors comprised of tertiary and quaternary amines, ammonium cations, sulfonium cations, or phosphonium cations, are prepared and fabricated into membranes that are subsequently imidized and converted into rigid-rod polyimide articles, such as membranes with desirable gas separation properties. A method of enhancing solubility of PAAS polymers in alcohols is also disclosed.

Dimple coalescence and liquid droplets distributions during phase separation in a pure fluid under microgravity.

Science.gov (United States)

Oprisan, Ana; Oprisan, Sorinel A; Hegseth, John J; Garrabos, Yves; Lecoutre-Chabot, Carole; Beysens, Daniel

2014-09-01

Phase separation has important implications for the mechanical, thermal, and electrical properties of materials. Weightless conditions prevent buoyancy and sedimentation from affecting the dynamics of phase separation and the morphology of the domains. In our experiments, sulfur hexafluoride (SF6) was initially heated about 1K above its critical temperature under microgravity conditions and then repeatedly quenched using temperature steps, the last one being of 3.6 mK, until it crossed its critical temperature and phase-separated into gas and liquid domains. Both full view (macroscopic) and microscopic view images of the sample cell unit were analyzed to determine the changes in the distribution of liquid droplet diameters during phase separation. Previously, dimple coalescences were only observed in density-matched binary liquid mixture near its critical point of miscibility. Here we present experimental evidences in support of dimple coalescence between phase-separated liquid droplets in pure, supercritical, fluids under microgravity conditions. Although both liquid mixtures and pure fluids belong to the same universality class, both the mass transport mechanisms and their thermophysical properties are significantly different. In supercritical pure fluids the transport of heat and mass are strongly coupled by the enthalpy of condensation, whereas in liquid mixtures mass transport processes are purely diffusive. The viscosity is also much smaller in pure fluids than in liquid mixtures. For these reasons, there are large differences in the fluctuation relaxation time and hydrodynamics flows that prompted this experimental investigation. We found that the number of droplets increases rapidly during the intermediate stage of phase separation. We also found that above a cutoff diameter of about 100 microns the size distribution of droplets follows a power law with an exponent close to -2, as predicted from phenomenological considerations.

XRD and SEM study on the phase separation and crystallization behavior for an amorphous Cu+ conductor

International Nuclear Information System (INIS)

Yang Yuan; Hou Jianguo; Yu Wenhai

1990-01-01

The X-ray diffraction (XRD) and scanning electron microscopy (SEM) study was carried out for an amorphous Cu + conductor 0.4 CuI-0.3 Cu 2 O-0.3 P 2 O 5 with the simultaneous conductivity measurement in the isothermal heat treament process. The results indicated that the initial amorphous material was phase-separated. In the course of time the separated amorphous phase disappeared, the crystalline γ-CuI and Cu 2 P 2 O 7 formed in sequence and grew up gradually. The correlation of the phase separation and crystallization behavior with the conductivity anomaly confirmed again the interface effect between different phases in amorphous fast ionic conductors and its universality

Colossal magnetoresistance and phase separation in manganite thin films

Science.gov (United States)

Srivastava, M. K.; Agarwal, V.; Kaur, A.; Singh, H. K.

2017-05-01

In the present work, polycrystalline Sm0.55Sr0.45MnO3 thin films were prepared on LSAT (001) single crystal substrates by ultrasonic nebulized spray pyrolysis technique. The X-ray diffraction θ-2θ scan reveals that these films (i) have very good crystallinity, (ii) are oriented along out-of-plane c-direction, and (iii) are under small tensile strain. The impact of oxygen vacancy results into (i) higher value of paramagnetic insulator (PMI) to ferromagnetic metal (FMM) transition temperature, i.e., TC/TIM, (ii) sharper PMI-FMM transition, (iii) higher value of magnetization and magnetic saturation moment, and (iv) higher value of magnetoresistance (˜99%). We suggest here that oxygen vacancy favors FMM phase while oxygen vacancy annihilation leads to antiferromagnetic-charge ordered insulator (AFM-COI) phase. The observed results have been explained in context of phase separation (PS) caused by different fractions of the competing FMM and AFM-COI phases.

Contaminating fibrin in CPD-blood: solubility in plasma and distribution in blood components following separation

International Nuclear Information System (INIS)

Skjonsberg, O.H.; Kierulf, P.; Gravem, K.; Fagerhol, M.K.; Godal, H.C.

1986-01-01

In order to estimate the solubility of contaminating fibrin in CPD-blood, thrombin induced fibrin polymerzation in CPD-plasma was examined by light scattering and fibrinopeptide A (FPA) determinations. In addition, I-125 fibrin monomer enriched CPD-blood was used to investigate fibrin monomer retention in blood bags and transfusion filters (170 microns) and fibrin distribution in blood components derived from CPD-blood. Initial fibrin polymerization in CPD-blood occurred after conversion of 15 per cent of the fibrinogen to fibrin, implying that substantial amounts of fibrin may be kept solubilized in CPD-blood bags. Only minor amounts of I-125 fibrin monomers were retained in blood bags (2.4 per cent) and in transfusion filters (2.9 per cent) after sham transfusions. After separating I-125-fibrin monomer enriched CPD-blood into its constituent components, the major part of fibrin (75.0 per cent) could be traced in the cryoprecipitate

Characteristics of phase transition and separation in a In-Ge-Sb-Te system

Energy Technology Data Exchange (ETDEWEB)

Park, Sung Jin [Institute of Physics and Applied Physics, Yonsei University, Seoul 120-749 (Korea, Republic of); Jang, Moon Hyung [Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, PA 19104 (United States); Park, Seung-Jong [Institute of Physics and Applied Physics, Yonsei University, Seoul 120-749 (Korea, Republic of); Cho, Mann-Ho, E-mail: mh.cho@yonsei.ac.kr [Institute of Physics and Applied Physics, Yonsei University, Seoul 120-749 (Korea, Republic of); Ko, Dae-Hong [Department of Material Science and Engineering, Yonsei University, Seoul 120-749 (Korea, Republic of)

2012-10-01

Highlights: Black-Right-Pointing-Pointer InGeSbTe films were fabricated via co-deposition stoichiometric GST and IST targets. Black-Right-Pointing-Pointer As the amount of IST was increased in InGeSbTe, the value for V{sub th} and the phase transition temperature were increased. Black-Right-Pointing-Pointer The phase separation in InGeSbTe is caused by differences in the enthalpy change for formation and different atomic concentrations. - Abstract: In-doped GeSbTe films were deposited by ion beam sputtering deposition (IBSD) using Ge{sub 2}Sb{sub 2}Te{sub 5} (GST) and In{sub 3}Sb{sub 1}Te{sub 2} (IST) as targets. The phase change characteristics of the resulting films were then investigated by electrical measurements, including static testing, in situ 4-point R{sub s} measurements, X-ray diffraction (XRD), transmission electron microscopy (TEM) and Raman spectroscopy. The threshold voltage of the films increased, with increasing levels of IST. This phenomenon is consistent with the increased crystallization temperature in X-ray data and in situ 4-point R{sub s} data. In addition, in In{sub 28}Ge{sub 12}Sb{sub 26}Te{sub 34}, multiple V{sub th} values with a stepwise change are observed. The minimum time for the crystallization of InGeSbTe films was shorter than that for GST. X-ray data and Raman data for the crystalline structure show that phase separation to In{sub 2}Te{sub 3} occurred in all of the InGeSbTe samples after annealing at 350 Degree-Sign C. Moreover, in the case of InGeSbTe films with high concentrations of In (28 at.%), Sb phase separation was also observed. The observed phases indicate that the origin of the phase separation of InGeSbTe films is from the enthalpy change of formation and differences in Ge-Te, In-Te, Sb-Te, In-Sb and In-In bond energies.

Tubing modifications for countercurrent chromatography (CCC): Stationary phase retention and separation efficiency.

Science.gov (United States)

Englert, Michael; Vetter, Walter

2015-07-16

Countercurrent chromatography (CCC) is a separation technique in which two immiscible liquid phases are used for the preparative purification of synthetic and natural products. In CCC the number of repetitive mixing and de-mixing processes, the retention of the stationary phase and the mass transfer between the liquid phases are significant parameters that influence the resolution and separation efficiency. Limited mass transfer is the main reason for peak broadening and a low number of theoretical plates along with impaired peak resolution in CCC. Hence, technical improvements with regard to column design and tubing modifications is an important aspect to enhance mixing and mass transfer. In this study we constructed a crimping tool which allowed us to make reproducible, semi-automated modifications of conventional round-shaped tubing. Six crimped tubing modifications were prepared, mounted onto multilayer coils which were subsequently installed in the CCC system. The stationary phase retention of the tubing modifications were compared to the conventional system with unmodified tubing in a hydrophobic, an intermediate and a hydrophilic two-phase solvent system. Generally, the tubing modifications provided higher capabilities to retain the stationary phase depending on the solvent system and flow rates. In the intermediate solvent system the separation efficiency was evaluated with a mixture of six alkyl p-hydroxybenzoates. The peak resolution could be increased up to 50% with one of the tubing modifications compared to the unmodified tubing. Using the most convincing tubing modification at fixed values for the stationary phase retention, a reasonable comparison to the unmodified tubing was achieved. The peak width could be reduced up to 49% and a strong positive impact at increased flow rates regarding peak resolution and theoretical plate number was observed compared to unmodified tubing. It could be concluded that the tubing modification enhanced the interphase

Preparing poly (caprolactone) micro-particles through solvent-induced phase separation

DEFF Research Database (Denmark)

Li, Xiaoqiang; Kanjwal, Muzafar Ahmed; Stephansen, Karen

2012-01-01

Poly (caprolactone) (PCL) particles with the size distribution from 1 to 100 μm were prepared through solvent-induced phase separation, in which polyvinyl-alcohol (PVA) was used as the matrix-forming polymer to stabilize PCL particles. The cloud point data of PCL-acetone-water was determined...

Standardization and application of the solid phase C1q radioimmunoassay using soluble tetanus toxoid-antitetanus immune complexes in sera of patients with chronic polyarthritis and Lupus erythematodes

International Nuclear Information System (INIS)

Menzel, E.J.; Steffen, C.; Smolen, J.

1982-01-01

Soluble tetanus-antitetanus immune complexes were prepared with affinity-chromatography and gel chromatography. Serial dilutions of these immune complex preparations were tested in a solid phase C1q radioimmunoassay. Soluble immune complexes as well as aggregated human gamma globulin of identical protein concentrations were comparatively investigated. Soluble immune complexes rendered a more sensitive standardization of RIA. According to these observations a relation between μg/ml equivalents of defined tetanus-antitetanus complexes and ng second antibody obtained in C1q-RIA was calculated. Upper limit of mean values and two standard deviations of ng second antibody obtained in investigations of 55 normal sera was designated as 1 unit immune complexes and regarded as border line of negative results. Multiplication of μg/ml immune complex equivalents of 1 unit led to a scale of 1 to 15 units, showing the area of positive results. According to these values a standardization curve was constructed allowing a conversion of ng-second antibody obtained in serum investigations into immune complex units equivalent to defined standard immune complexes. With this curve investigation results of 56 RA sera and 21 SLE sera were expressed in the range of units, making a distinct gradation of positive results and a clear cut separation of positive and negative results possible. SLE sera of patients in acute stage showed highly positive results. (orig.) [de

Standardization and application of the solid phase C1q radioimmunoassay using soluble tetanus toxoid-antitetanus immune complexes in sera of patients with chronic polyarthritis and Lupus erythematodes

Energy Technology Data Exchange (ETDEWEB)

Menzel, E J; Steffen, C; Smolen, J

1982-11-22

Soluble tetanus-antitetanus immune complexes were prepared with affinity-chromatography and gel chromatography. Serial dilutions of these immune complex preparations were tested in a solid phase C1q radioimmunoassay. Soluble immune complexes as well as aggregated human gamma globulin of identical protein concentrations were comparatively investigated. Soluble immune complexes rendered a more sensitive standardization of RIA. According to these observations a relation between ..mu..g/ml equivalents of defined tetanus-antitetanus complexes and ng second antibody obtained in C1q-RIA was calculated. Upper limit of mean values and two standard deviations of ng second antibody obtained in investigations of 55 normal sera was designated as 1 unit immune complexes and regarded as border line of negative results. Multiplication of ..mu..g/ml immune complex equivalents of 1 unit led to a scale of 1 to 15 units, showing the area of positive results. According to these values a standardization curve was constructed allowing a conversion of ng-second antibody obtained in serum investigations into immune complex units equivalent to defined standard immune complexes. With this curve investigation results of 56 RA sera and 21 SLE sera were expressed in the range of units, making a distinct gradation of positive results and a clear cut separation of positive and negative results possible. SLE sera of patients in acute stage showed highly positive results.

Multi-Phase Equilibrium and Solubilities of Aromatic Compounds and Inorganic Compounds in Sub- and Supercritical Water: A Review.

Science.gov (United States)

Liu, Qinli; Ding, Xin; Du, Bowen; Fang, Tao

2017-11-02

Supercritical water oxidation (SCWO), as a novel and efficient technology, has been applied to wastewater treatment processes. The use of phase equilibrium data to optimize process parameters can offer a theoretical guidance for designing SCWO processes and reducing the equipment and operating costs. In this work, high-pressure phase equilibrium data for aromatic compounds+water systems and inorganic compounds+water systems are given. Moreover, thermodynamic models, equations of state (EOS) and empirical and semi-empirical approaches are summarized and evaluated. This paper also lists the existing problems of multi-phase equilibria and solubility studies on aromatic compounds and inorganic compounds in sub- and supercritical water.

Effect of cyclodextrin complexation on the aqueous solubility and solubility/dose ratio of praziquantel.

Science.gov (United States)

Maragos, Stratos; Archontaki, Helen; Macheras, Panos; Valsami, Georgia

2009-01-01

Praziquantel (PZQ), the primary drug of choice in the treatment of schistosomiasis, is a highly lipophilic drug that possesses high permeability and low aqueous solubility and is, therefore, classified as a Class II drug according to the Biopharmaceutics Classification System (BCS). In this work, beta-cyclodextrin (beta-CD) and hydroxypropyl-beta-cyclodextrin (HP-beta-CD) were used in order to determine whether increasing the aqueous solubility of a drug by complexation with CDs, a BCS-Class II compound like PZQ could behave as BCS-Class I (highly soluble/highly permeable) drug. Phase solubility and the kneading and lyophilization techniques were used for inclusion complex preparation; solubility was determined by UV spectroscopy. The ability of the water soluble polymer polyvinylpyrolidone (PVP) to increase the complexation and solubilization efficiency of beta-CD and HP-beta-CD for PZQ was examined. Results showed significant improvement of PZQ solubility in the presence of both cyclodextrins but no additional effect in the presence of PVP. The solubility/dose ratios values of PZQ-cyclodextrin complexes calculated considering the low (150 mg) and the high dose (600 mg) of PZQ, used in practice, indicate that PZQ complexation with CDs may result in drug dosage forms that would behave as a BCS-Class I depending on the administered dose.

Two complementary reversed-phase separations for comprehensive coverage of the semipolar and nonpolar metabolome.

Science.gov (United States)

Naser, Fuad J; Mahieu, Nathaniel G; Wang, Lingjue; Spalding, Jonathan L; Johnson, Stephen L; Patti, Gary J

2018-02-01

Although it is common in untargeted metabolomics to apply reversed-phase liquid chromatography (RPLC) and hydrophilic interaction liquid chromatography (HILIC) methods that have been systematically optimized for lipids and central carbon metabolites, here we show that these established protocols provide poor coverage of semipolar metabolites because of inadequate retention. Our objective was to develop an RPLC approach that improved detection of these metabolites without sacrificing lipid coverage. We initially evaluated columns recently released by Waters under the CORTECS line by analyzing 47 small-molecule standards that evenly span the nonpolar and semipolar ranges. An RPLC method commonly used in untargeted metabolomics was considered a benchmarking reference. We found that highly nonpolar and semipolar metabolites cannot be reliably profiled with any single method because of retention and solubility limitations of the injection solvent. Instead, we optimized a multiplexed approach using the CORTECS T3 column to analyze semipolar compounds and the CORTECS C 8 column to analyze lipids. Strikingly, we determined that combining these methods allowed detection of 41 of the total 47 standards, whereas our reference RPLC method detected only 10 of the 47 standards. We then applied credentialing to compare method performance at the comprehensive scale. The tandem method showed more than a fivefold increase in credentialing coverage relative to our RPLC benchmark. Our results demonstrate that comprehensive coverage of metabolites amenable to reversed-phase separation necessitates two reconstitution solvents and chromatographic methods. Thus, we suggest complementing HILIC methods with a dual T3 and C 8 RPLC approach to increase coverage of semipolar metabolites and lipids for untargeted metabolomics. Graphical abstract Analysis of semipolar and nonpolar metabolites necessitates two reversed-phase chromatography (RPLC) methods, which extend metabolome coverage more

Enhancement of biomembrane functions under phase-separated conditions: A self-organized criticality phenomenon?

International Nuclear Information System (INIS)

Eze, M.O.; Chela Flores, J.

1993-12-01

Self-organized criticality (SOC) is hereby proposed as a possible physical basis for explaining observations in the temperature-dependence of the rates of biological membrane-associated events. The biomembrane undergoes a reversible, cooperative, thermotropic gel-to-liquid crystalline phase transition which is broad, and involves lateral phase separation. The lateral phase separated (rather than the totally gel-, or the totally liquid crystalline-) membrane state has been observed to be the state in which vital membrane functions are facilitated. The membrane in this unique state is viewed, for our purposes here, as a dynamical, extended dissipative system with spatial and temporal degrees of freedom, exhibiting power law behaviour, typical of the self-organized critical state. Experiments are suggested for verifying this hypothesis. (author). 30 refs

Predictions of Phase Separation in Three-Component Lipid Membranes by the MARTINI Force Field

DEFF Research Database (Denmark)

Davis, Ryan S.; Sunil Kumar, P. B.; Sperotto, Maria Maddalena

2013-01-01

The phase behavior of the coarse-grained MARTINI model for three-component lipid bilayers composed of dipalmytoyl-phosphatidylcholine (DPPC), cholesterol (Chol), and an unsaturated phosphatidylcholine (PC) was systematically investigated by molecular dynamics simulations. The aim of this study...... is to understand which types of unsaturated PC induce the formation of thermodynamically stable coexisting phases when added to mixtures of DPPC and Chol and to unravel the mechanisms that drive phase separation in such three-component mixtures. Our simulations indicate that the currently used MARTINI force field...... PCs, such as dilinoleyl-phosphatidylcholine (DUPC) and diarachidonoyl-phosphatidylcholine (DAPC). Through systematic tweaking of the interactions between the hydrophobic groups of the PC molecules, we show that the appearance of phase separation in three-component lipid bilayers, as modeled through...

Solvent annealing induced phase separation and dewetting in PMMA∕SAN blend film: film thickness and solvent dependence.

Science.gov (United States)

You, Jichun; Zhang, Shuangshuang; Huang, Gang; Shi, Tongfei; Li, Yongjin

2013-06-28

The competition between "dewetting" and "phase separation" behaviors in polymer blend films attracts significant attention in the last decade. The simultaneous phase separation and dewetting in PMMA∕SAN [poly(methyl methacrylate) and poly(styrene-ran-acrylonitrile)] blend ultrathin films upon solvent annealing have been observed for the first time in our previous work. In this work, film thickness and annealing solvent dependence of phase behaviors in this system has been investigated using atomic force microscopy and grazing incidence small-angle X-ray scattering (GISAXS). On one hand, both vertical phase separation and dewetting take place upon selective solvent vapor annealing, leading to the formation of droplet∕mimic-film structures with various sizes (depending on original film thickness). On the other hand, the whole blend film dewets the substrate and produces dispersed droplets on the silicon oxide upon common solvent annealing. GISAXS results demonstrate the phase separation in the big dewetted droplets resulted from the thicker film (39.8 nm). In contrast, no period structure is detected in small droplets from the thinner film (5.1 nm and 9.7 nm). This investigation indicates that dewetting and phase separation in PMMA∕SAN blend film upon solvent annealing depend crucially on the film thickness and the atmosphere during annealing.

Purification of flavonoids from licorice using an off-line preparative two-dimensional normal-phase liquid chromatography/reversed-phase liquid chromatography method.

Science.gov (United States)

Fan, Yunpeng; Fu, Yanhui; Fu, Qing; Cai, Jianfeng; Xin, Huaxia; Dai, Mei; Jin, Yu

2016-07-01

An orthogonal (71.9%) off-line preparative two-dimensional normal-phase liquid chromatography/reversed-phase liquid chromatography method coupled with effective sample pretreatment was developed for separation and purification of flavonoids from licorice. Most of the nonflavonoids were firstly removed using a self-made Click TE-Cys (60 μm) solid-phase extraction. In the first dimension, an industrial grade preparative chromatography was employed to purify the crude flavonoids. Click TE-Cys (10 μm) was selected as the stationary phase that provided an excellent separation with high reproducibility. Ethyl acetate/ethanol was selected as the mobile phase owing to their excellent solubility for flavonoids. Flavonoids co-eluted in the first dimension were selected for further purification using reversed-phase liquid chromatography. Multiple compounds could be isolated from one normal-phase fraction and some compounds with bad resolution in one-dimensional liquid chromatography could be prepared in this two-dimensional system owing to the orthogonal separation. Moreover, this two-dimensional liquid chromatography method was beneficial for the preparation of relatively trace flavonoid compounds, which were enriched in the first dimension and further purified in the second dimension. Totally, 24 flavonoid compounds with high purity were obtained. The results demonstrated that the off-line two-dimensional liquid chromatography method was effective for the preparative separation and purification of flavonoids from licorice. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

How to separate ionic liquids: Use of Hydrophilic Interaction Liquid Chromatography and mixed mode phases

International Nuclear Information System (INIS)

Lamouroux, C.

2011-01-01

This chromatographic study deals with the development of a convenient and versatile method to separate Room Temperature Ionic Liquids. Different modes of chromatography were studied. The study attempts to answer the following question: 'what were the most important interactions for the separation of ionic liquids?'. The results show that the essential interactions to assure a good retention of RTILs are the ionic ones and that hydrophobic interactions play a role in the selectivity of the separation. The separation of five imidazolium salt with a traditional dial columns in Hydrophilic Interaction Chromatography (HILIC) was demonstrated. It shows that neutral diol grafted column allows an important retention that we assume is due to the capability of diol to develop a thick layer of water. Furthermore, stationary phase based on mixed interaction associating ion exchange and hydrophobic properties were studied. Firstly, it will be argued that it is possible to separate RTILs with a convenient retention and resolution according to a reverse phase elution with the Primesep columns made of a brush type long alkyl chain with an embedded negatively charged functional group. Secondly, a successful separation of RTILs in HILIC mode with a mixed phase column containing a cationic exchanger and a hydrophobic octyl chain length will be demonstrated. (author)

Comparison of liquid and supercritical fluid chromatography mobile phases for enantioselective separations on polysaccharide stationary phases.

Science.gov (United States)

Khater, Syame; Lozac'h, Marie-Anne; Adam, Isabelle; Francotte, Eric; West, Caroline

2016-10-07

Analysis and production of enantiomerically pure compounds is a major topic of interest when active pharmaceutical ingredients are concerned. Enantioselective chromatography has become a favourite both at the analytical and preparative scales. High-performance liquid chromatography (HPLC) and supercritical fluid chromatography (SFC) are dominating the scene and are often seen as complementary techniques. Nowadays, for economic and ecologic reasons, SFC may be preferred over normal-phase HPLC (NPLC) as it allows significant reductions in solvent consumption. However, the transfer of NPLC methods to SFC is not always straightforward. In this study, we compare the retention of achiral molecules and separation of enantiomers under supercritical fluid (carbon dioxide with ethanol or isopropanol) and liquid normal-phase (heptane with ethanol or isopropanol) elution modes with polysaccharide stationary phases in order to explore the differences between the retention and enantioseparation properties between the two modes. Chemometric methods (namely quantitative structure-retention relationships and discriminant analysis) are employed to compare the results obtained on a large set of analytes (171 achiral probes and 97 racemates) and gain some understanding on the retention and separation mechanisms. The results indicate that, contrary to popular belief, carbon dioxide - solvent SFC mobile phases are often weaker eluents than liquid mobile phases. It appears that SFC and NPLC elution modes provide different retention mechanisms. While some enantioseparations are unaffected, facilitating the transfer between the two elution modes, other enantioseparations may be drastically different due to different types and strength of interactions contributing to enantioselectivity. Copyright © 2016 Elsevier B.V. All rights reserved.

Current-induced transition from particle-by-particle to concurrent intercalation in phase-separating battery electrodes

KAUST Repository

Li, Yiyang; El Gabaly, Farid; Ferguson, Todd R.; Smith, Raymond B.; Bartelt, Norman C.; Sugar, Joshua D.; Fenton, Kyle R.; Cogswell, Daniel A.; Kilcoyne, A. L. David; Tyliszczak, Tolek; Bazant, Martin Z.; Chueh, William C.

2014-01-01

©2014 Macmillan Publishers Limited. All rights reserved. Many battery electrodes contain ensembles of nanoparticles that phase-separate on (de)intercalation. In such electrodes, the fraction of actively intercalating particles directly impacts cycle life: a vanishing population concentrates the current in a small number of particles, leading to current hotspots. Reports of the active particle population in the phase-separating electrode lithium iron phosphate (LiFePO 4; LFP) vary widely, ranging from near 0% (particle-by-particle) to 100% (concurrent intercalation). Using synchrotron-based X-ray microscopy, we probed the individual state-of-charge for over 3,000 LFP particles. We observed that the active population depends strongly on the cycling current, exhibiting particle-by-particle-like behaviour at low rates and increasingly concurrent behaviour at high rates, consistent with our phase-field porous electrode simulations. Contrary to intuition, the current density, or current per active internal surface area, is nearly invariant with the global electrode cycling rate. Rather, the electrode accommodates higher current by increasing the active particle population. This behaviour results from thermodynamic transformation barriers in LFP, and such a phenomenon probably extends to other phase-separating battery materials. We propose that modifying the transformation barrier and exchange current density can increase the active population and thus the current homogeneity. This could introduce new paradigms to enhance the cycle life of phase-separating battery electrodes.

Current-induced transition from particle-by-particle to concurrent intercalation in phase-separating battery electrodes.

Science.gov (United States)

Li, Yiyang; El Gabaly, Farid; Ferguson, Todd R; Smith, Raymond B; Bartelt, Norman C; Sugar, Joshua D; Fenton, Kyle R; Cogswell, Daniel A; Kilcoyne, A L David; Tyliszczak, Tolek; Bazant, Martin Z; Chueh, William C

2014-12-01

Many battery electrodes contain ensembles of nanoparticles that phase-separate on (de)intercalation. In such electrodes, the fraction of actively intercalating particles directly impacts cycle life: a vanishing population concentrates the current in a small number of particles, leading to current hotspots. Reports of the active particle population in the phase-separating electrode lithium iron phosphate (LiFePO4; LFP) vary widely, ranging from near 0% (particle-by-particle) to 100% (concurrent intercalation). Using synchrotron-based X-ray microscopy, we probed the individual state-of-charge for over 3,000 LFP particles. We observed that the active population depends strongly on the cycling current, exhibiting particle-by-particle-like behaviour at low rates and increasingly concurrent behaviour at high rates, consistent with our phase-field porous electrode simulations. Contrary to intuition, the current density, or current per active internal surface area, is nearly invariant with the global electrode cycling rate. Rather, the electrode accommodates higher current by increasing the active particle population. This behaviour results from thermodynamic transformation barriers in LFP, and such a phenomenon probably extends to other phase-separating battery materials. We propose that modifying the transformation barrier and exchange current density can increase the active population and thus the current homogeneity. This could introduce new paradigms to enhance the cycle life of phase-separating battery electrodes.

Current-induced transition from particle-by-particle to concurrent intercalation in phase-separating battery electrodes

KAUST Repository

Li, Yiyang

2014-09-14

©2014 Macmillan Publishers Limited. All rights reserved. Many battery electrodes contain ensembles of nanoparticles that phase-separate on (de)intercalation. In such electrodes, the fraction of actively intercalating particles directly impacts cycle life: a vanishing population concentrates the current in a small number of particles, leading to current hotspots. Reports of the active particle population in the phase-separating electrode lithium iron phosphate (LiFePO 4; LFP) vary widely, ranging from near 0% (particle-by-particle) to 100% (concurrent intercalation). Using synchrotron-based X-ray microscopy, we probed the individual state-of-charge for over 3,000 LFP particles. We observed that the active population depends strongly on the cycling current, exhibiting particle-by-particle-like behaviour at low rates and increasingly concurrent behaviour at high rates, consistent with our phase-field porous electrode simulations. Contrary to intuition, the current density, or current per active internal surface area, is nearly invariant with the global electrode cycling rate. Rather, the electrode accommodates higher current by increasing the active particle population. This behaviour results from thermodynamic transformation barriers in LFP, and such a phenomenon probably extends to other phase-separating battery materials. We propose that modifying the transformation barrier and exchange current density can increase the active population and thus the current homogeneity. This could introduce new paradigms to enhance the cycle life of phase-separating battery electrodes.

Separation process for lanthanides based on solvation properties of non ionic surfactants

International Nuclear Information System (INIS)

Draye, M.; Favre-Reguillon, A.; Foos, J.; Cote, G.

2004-01-01

In the present study, cloud-point extraction is used with a lipophilic chelating agent (8-hydroxyquinoline) to extract and separate lanthanum (III) and gadolinium (III) from an aqueous solution. The methodology used is based on the formation of lanthanide (III) organic complexes that are soluble in a micellar phase of non-ionic surfactant. The lanthanide (III) complexes are then extracted into the surfactant-rich phase at a temperature above the cloud-point temperature. The cloud-point temperature, the structure of the lipophilic part of the nonionic surfactant and the chelating agent - metal molar ratio are identified as factors determining the extraction efficiency and selectivity. With Triton X-114, high selectivity and decontamination factor for Gd(III) is observed indicating that micelle mediated extraction involving cloud-point extraction is promising for the specific separation of actinide ions from nuclear waste solution. (authors)

Cooperation and Phase Separation Driven by a Coevolving Snowdrift Game

International Nuclear Information System (INIS)

Du Peng; Xu Chen; Zhang Wen

2015-01-01

We investigate the cooperative behavior and the phase separation in a coevolving system. Agents in the system constructed by a regular random network initially play the snowdrift game with their neighbors. They try to obtain a better competing environment by imitating a neighbor's more successful strategy or cutting the connection to a defective neighbor and randomly rewiring to another agent so as to seek a better neighborhood. The dynamic process of strategy imitation and relationship among agents due to rewiring neighbors may drive the system into different states. The simulation results show that there are three different phases in the q-r plane, where q is the rewiring probability and r is the cost-to-benefit ratio. One is a static phase of a pure cooperative cluster with a few isolated defectors. The other two belong to active phases with one of a main mixed-strategy cluster and the other of a pure defective state. We find that a simple mean field theory can predict correctly the static phase and the active phase of the main mixed-strategy cluster. The theoretical boundary line between the two phases is in good agreement with the simulation result. (paper)

Liquid-Liquid Phase Separation in Model Nuclear Waste Glasses: A Solid-State Double-Resonance NMR Study

Energy Technology Data Exchange (ETDEWEB)

Martineau, Ch.; Michaelis, V.K.; Kroeker, S. [Univ Manitoba, Dept Chem, Winnipeg, MB R3T 2N2 (Canada); Schuller, S. [CEA Valrho Marcoule, LDMC, SECM, DTCD, DEN, F-30207 Bagnols Sur Ceze (France)

2010-07-01

Double-resonance nuclear magnetic resonance (NMR) techniques are used in addition to single-resonance NMR experiments to probe the degree of mixing between network-forming cations Si and B, along with the modifier cations Cs{sup +} and Na{sup +} in two molybdenum-bearing model nuclear waste glasses. The double-resonance experiments involving {sup 29}Si in natural abundance are made possible by the implementation of a CPMG pulse-train during the acquisition period of the usual REDOR experiments. For the glass with lower Mo content, the NMR results show a high degree of Si-B mixing, as well as an homogeneous distribution of the cations within the borosilicate network, characteristic of a non-phase-separated glass. For the higher-Mo glass, a decrease of B-Si(Q{sup 4}) mixing is observed, indicating phase separation. {sup 23}Na and {sup 133}Cs NMR results show that although the Cs{sup +} cations, which do not seem to be influenced by the molybdenum content, are spread within the borate network, there is a clustering of the Na{sup +} cations, very likely around the molybdate units. The segregation of a Mo-rich region with Na{sup +} cations appears to shift the bulk borosilicate glass composition toward the metastable liquid liquid immiscibility region and induce additional phase separation. Although no crystallization is observed in the present case, this liquid liquid phase separation is likely to be the first stage of crystallization that can occur at higher Mo loadings or be driven by heat treatment. From this study emerges a consistent picture of the nature and extent of such phase separation phenomena in Mo-bearing glasses, and demonstrates the potential of double-resonance NMR methods for the investigation of phase separation in amorphous materials. (authors)

Phase separation like dynamics during Myxococcus xanthus fruiting body formation

Science.gov (United States)

Liu, Guannan; Thutupalli, Shashi; Wigbers, Manon; Shaevitz, Joshua

2015-03-01

Collective motion exists in many living organisms as an advantageous strategy to help the entire group with predation, forage, and survival. However, the principles of self-organization underlying such collective motions remain unclear. During various developmental stages of the soil-dwelling bacterium, Myxococcus xanthus, different types of collective motions are observed. In particular, when starved, M. xanthus cells eventually aggregate together to form 3-dimensional structures (fruiting bodies), inside which cells sporulate in response to the stress. We study the fruiting body formation process as an out of equilibrium phase separation process. As local cell density increases, the dynamics of the aggregation M. xanthus cells switch from a spatio-temporally random process, resembling nucleation and growth, to an emergent pattern formation process similar to a spinodal decomposition. By employing high-resolution microscopy and a video analysis system, we are able to track the motion of single cells within motile collective groups, while separately tuning local cell density, cell velocity and reversal frequency, probing the multi-dimensional phase space of M. xanthus development.

Test plan: Effects of phase separation on waste loading for high level waste glasses

International Nuclear Information System (INIS)

Jantzen, C.M.

2000-01-01

As part of the Tanks Focus Area's (TFA) effort to increase waste loading for high-level waste (HLW) vitrification at various facilities in the Department of Energy (DOE) complex, the occurrence of phase separation in waste glasses spanning the Savannah River Site (SRS) and Idaho National Engineering and Environmental Laboratory (INEEL) composition ranges were studied during FY99. The type, extent, and impact of phase separation on glass durability for a series of HLW glasses, e.g., SRS-type and INEEL-type, were examined

A theory of phase separation in asphaltene-micellar solutions

Energy Technology Data Exchange (ETDEWEB)

Pacheco Sanchez, Juan H. [Instituto Mexicano del Petroleo, Mexico D.F. (Mexico)

2001-08-01

A theory of phase separation in micellar solutions of asphaltene in aromatic hydrocarbons was reported in this paper, based on both the approach of the phase behavior of amphiphile/water micelles, and the self-association of asphaltene in aromatic core. Several experimental techniques have been used by different investigators showing the existence of some kind of critical micellar concentration (CMC) on asphaltenes in aromatic solutions. So, at least asphaltene-monomer and asphaltene-micellar phases are experimentally demonstrated facts. These two phases are the main purpose in this report on a theoretical model. Some results show the temperature versus asphaltene concentration phase diagram. The phase diagram is examined against the limited critical micelle concentration data for asphaltenes-in-toluene systems. Such phase diagram is also qualitatively examined against an experimental demonstration of phase separation. The asphaltene-micelle growth depends on the parameter K responsible for the shape and size of it. At the same time, parameter K depends on both the number of asphaltene-monomer associated in the asphaltene-micelle, and the chemical potentials in the interior and in the periphery of the micelle. An expression for getting the number of asphaltene-monomers self-associated in the asphaltene-micelle was obtained. [Spanish] Se reporta una teoria de separacion de fases en soluciones micelares de asfalteno en hidrocarburos aromaticos, basada tanto en la conducta de fase de micelas formadas por anififilos en agua como en la autoasociacion de asfaltenos en nucleos aromaticos. Se han usado diversas tecnicas experimentales por diferentes investigadores que demuestran la existancia de algun tipo de concentracion micelar critica (CMC) de soluciones de asfaltenos en aromaticos. Entonces, al menos las fases de asfalteno-monomerico y de asfalteno-micelar son hechos experimentalmente demostrados. Esta dos fases son el principal proposito de este reporte en un modelo

Battery Separator Membrane Having a Selectable Thermal Shut-Down Temperature, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — This Small Business Innovation Research Phase II proposal to NASA requests $596,750.96 support for Policell Technologies, Inc. to develop a series of separator...

Phase separation in strongly correlated electron systems with two types of charge carriers

International Nuclear Information System (INIS)

Kugel, K.I.; Rakhmanov, A.L.; Sboychakov, A.O.

2007-01-01

Full text: A competition between the localization of the charge carriers due to Jahn-Teller distortions and the energy gain due to their delocalization in doped manganite and related magnetic oxides is analyzed based on a Kondo-lattice type model. The resulting effective Hamiltonian is, in fact, a generalization of the Falicov-Kimball model. We find that the number of itinerant charge carriers can be significantly lower than that implied by the doping level x. The phase diagram of the model in the T plane is constructed. The system exhibits magnetic ordered (antiferromagnetic, ferromagnetic, or canted) states as well the paramagnetic states with zero and nonzero density of the itinerant electrons. It is shown that a phase-separation is favorable in energy for a wide doping range. The characteristic size of inhomogeneities in a phase-separated state is of the order of several lattice constants. We also analyzed the two-band Hubbard model in the limit of strong on-site Coulomb repulsion. It was shown that such a system has a tendency to phase separation into the regions with different charge densities even in the absence of magnetic or any other ordering, if the ratio of the bandwidths is large enough. The work was supported by the European project CoMePhS and by the Russian Foundation for Basic Research, project no. 05-02-17600. (authors)

Polymer depletion-driven cluster aggregation and initial phase separation in charged nanosized colloids

Science.gov (United States)

Gögelein, Christoph; Nägele, Gerhard; Buitenhuis, Johan; Tuinier, Remco; Dhont, Jan K. G.

2009-05-01

We study polymer depletion-driven cluster aggregation and initial phase separation in aqueous dispersions of charge-stabilized silica spheres, where the ionic strength and polymer (dextran) concentration are systematically varied, using dynamic light scattering and visual observation. Without polymers and for increasing salt and colloid content, the dispersions become increasingly unstable against irreversible cluster formation. By adding nonadsorbing polymers, a depletion-driven attraction is induced, which lowers the stabilizing Coulomb barrier and enhances the cluster growth rate. The initial growth rate increases with increasing polymer concentration and decreases with increasing polymer molar mass. These observations can be quantitatively understood by an irreversible dimer formation theory based on the classical Derjaguin, Landau, Verwey, and Overbeek pair potential, with the depletion attraction modeled by the Asakura-Oosawa-Vrij potential. At low colloid concentration, we observe an exponential cluster growth rate for all polymer concentrations considered, indicating a reaction-limited aggregation mechanism. At sufficiently high polymer and colloid concentrations, and lower salt content, a gas-liquidlike demixing is observed initially. Later on, the system separates into a gel and fluidlike phase. The experimental time-dependent state diagram is compared to the theoretical equilibrium phase diagram obtained from a generalized free-volume theory and is discussed in terms of an initial reversible phase separation process in combination with irreversible aggregation at later times.

Resveratrol cocrystals with enhanced solubility and tabletability.

Science.gov (United States)

Zhou, Zhengzheng; Li, Wanying; Sun, Wei-Jhe; Lu, Tongbu; Tong, Henry H Y; Sun, Changquan Calvin; Zheng, Ying

2016-07-25

Two new 1:1 cocrystals of resveratrol (RES) with 4-aminobenzamide (RES-4ABZ) and isoniazid (RES-ISN) were synthesized by liquid assisted grinding (LAG) and rapid solvent removal (RSR) methods using ethanol as solvent. Their physiochemical properties were characterized using PXRD, DSC, solid state and solution NMR, FT-IR, and HPLC. Pharmaceutically relevant properties, including tabletability, solubility, intrinsic dissolution rate, and hygroscopicity, were evaluated. Temperature-composition phase diagram for RES-ISN cocrystal system was constructed from DSC data. Both cocrystals show higher solubility than resveratrol over a broad range of pH. They are phase stable and non-hygroscopic even under high humidity conditions. Importantly, both cocrystals exhibit improved solubility and tabletability compared with RES, which make them more suitable candidates for tablet formulation development. Copyright © 2016 Elsevier B.V. All rights reserved.

Solid dispersions: a strategy for poorly aqueous soluble drugs and technology updates.

Science.gov (United States)

Alam, Mohd Aftab; Ali, Raisuddin; Al-Jenoobi, Fahad Ibrahim; Al-Mohizea, Abdullah M

2012-11-01

Present article reviews solid dispersion (SD) technologies and other patented inventions in the area of pharmaceutical SDs, which provide stable amorphous SDs. The review briefly compiles different techniques for preparing SDs, their applications, characterization of SDs, types of SDs and also elaborates the carriers used to prepare SDs. The advantages of recently introduced SD technologies such as RightSize(™), closed-cycle spray drying (CSD), Lidose® are summarized. Stability-related issues like phase separation, re-crystallization and methods to curb these problems are also discussed. A patented carrier-screening tool for predicting physical stability of SDs on the basis of drug-carrier interaction is explained. Applications of SD technique in controlled drug delivery systems and cosmetics are explored. Review also summarizes the carriers such as Soluplus®, Neusilin®, Solumer(TM) used to prepare stable amorphous SD. Binary and ternary SDs are found to be more stable and provide better enhancement of solubility or dissolution of poorly water-soluble drugs. The use of surfactants in the carrier system of SD is a recent trend. Surfactants and polymers provide stability against re-crystallization of SDs, surfactants also improve solubility and dissolution of drug.

Physico-chemical separation process of nanoparticles in cosmetic formulations

International Nuclear Information System (INIS)

Marín, R. R. Retamal; Babick, F.; Stintz, M.

2017-01-01

Understanding the world of nanoparticles, especially their interactions with the environment, begins with their correct detection and successive quantification. To achieve this purpose, one needs to perform correctly developed standard operating procedures (SOPs). Furthermore, the study of nanoparticles frequently requires their characterisation in complex media (e.g. in cosmetic formulations). In this study, a set of sample preparation procedures for the detection and extraction of NMs in emulsion-based formulations is proposed and their performance for model and real-life products is discussed. A separation or extraction of lipid phases is achieved by means of organic solvents. The polarity of the lipid phases is decisive for selecting an optimum solvent. The use of the Hansen Solubility Parameters (HSP) may clearly support this decision. (paper)

Anisotropic imprint of amorphization and phase separation in manganite thin films via laser interference irradiation

KAUST Repository

Ding, Junfeng; Lin, Zhipeng; Wu, Jianchun; Dong, Zhili; Wu, Tao

2014-01-01

Materials with mesoscopic structural and electronic phase separation, either inherent from synthesis or created via external means, are known to exhibit functionalities absent in the homogeneous counterparts. One of the most notable examples is the colossal magnetoresistance discovered in mixed-valence manganites, where the coexistence of nano-to micrometer-sized phase-separated domains dictates the magnetotransport. However, it remains challenging to pattern and process such materials into predesigned structures and devices. In this work, a direct laser interference irradiation (LII) method is employed to produce periodic stripes in thin films of a prototypical phase-separated manganite Pr0.65(Ca0.75Sr0.25)0.35MnO3 (PCSMO). LII induces selective structural amorphization within the crystalline PCSMO matrix, forming arrays with dimensions commensurate with the laser wavelength. Furthermore, because the length scale of LII modification is compatible to that of phase separation in PCSMO, three orders of magnitude of increase in magnetoresistance and significant in-plane transport anisotropy are observed in treated PCSMO thin films. Our results show that LII is a rapid, cost-effective and contamination-free technique to tailor and improve the physical properties of manganite thin films, and it is promising to be generalized to other functional materials.

Anisotropic imprint of amorphization and phase separation in manganite thin films via laser interference irradiation

KAUST Repository

Ding, Junfeng

2014-09-16

Materials with mesoscopic structural and electronic phase separation, either inherent from synthesis or created via external means, are known to exhibit functionalities absent in the homogeneous counterparts. One of the most notable examples is the colossal magnetoresistance discovered in mixed-valence manganites, where the coexistence of nano-to micrometer-sized phase-separated domains dictates the magnetotransport. However, it remains challenging to pattern and process such materials into predesigned structures and devices. In this work, a direct laser interference irradiation (LII) method is employed to produce periodic stripes in thin films of a prototypical phase-separated manganite Pr0.65(Ca0.75Sr0.25)0.35MnO3 (PCSMO). LII induces selective structural amorphization within the crystalline PCSMO matrix, forming arrays with dimensions commensurate with the laser wavelength. Furthermore, because the length scale of LII modification is compatible to that of phase separation in PCSMO, three orders of magnitude of increase in magnetoresistance and significant in-plane transport anisotropy are observed in treated PCSMO thin films. Our results show that LII is a rapid, cost-effective and contamination-free technique to tailor and improve the physical properties of manganite thin films, and it is promising to be generalized to other functional materials.

Formation of structural steady states in lamellar/sponge phase-separating fluids under shear flow

Science.gov (United States)

Panizza, P.; Courbin, L.; Cristobal, G.; Rouch, J.; Narayanan, T.

2003-05-01

We investigate the effect of shear flow on a lamellar-sponge phase-separating fluid when subjected to shear flow. We show the existence of two different steady states (droplets and ribbons structures) whose nature does not depend on the way to reach the two-phase unstable region of the phase diagram (temperature quench or stirring). The transition between ribbons and droplets is shear thickening and its nature strongly depends on what dynamical variable is imposed. If the stress is fixed, flow visualization shows the existence of shear bands at the transition, characteristic of coexistence in the cell between ribbons and droplets. In this shear-banding region, the viscosity oscillates. When the shear rate is fixed, no shear bands are observed. Instead, the transition exhibits a hysteretic behavior leading to a structural bi-stability of the phase-separating fluid under flow.

Relativistic quasiparticle random phase approximation with a separable pairing force

International Nuclear Information System (INIS)

Tian Yuan; Ma Zhongyu; Ring Peter

2009-01-01

In our previous work, we introduced a separable pairing force for relativistic Hartree-Bogoliubov calculations. This force was adjusted to reproduce the pairing properties of the Gogny force in nuclear matter. By using the well known techniques of Talmi and Moshinsky it can be expanded in a series of separable terms and converges quickly after a few terms. It was found that the pairing properties can be depicted on almost the same footing as the original pairing interaction, not only in nuclear matter, but also in finite nuclei. In this study, we construct a relativistic quasiparticle random phase approximation (RQRPA) with this separable pairing interaction and calculate the excitation energies of the first excited 2 + states and reduced B(E2; 0 + →2 + ) transition rates for a chain of Sn isotopes in RQRPA. Compared with the results of the full Gogny force, we find that this simple separable pairing interaction can describe the pairing properties of the excited vibrational states as well as the original pairing interaction. (authors)

The microstructure and rheology of homogeneous and phase separated gelatine gels

NARCIS (Netherlands)

Ersch, C.; Linden, E. van der; Venema, P.; Martin, A.

2016-01-01

The gelation of gelatine in mixtures of gelatine (type A or type B) and globular proteins (Whey Protein Isolate (WPI), Whey Protein Aggregates (WPA) and Soy Protein Isolate (SPI)) was studied with a focus on their phase separation during gelation. Confocal laser scanning microscopy, visual

X-radiation effect on soluble proteins of gastric mucosa

International Nuclear Information System (INIS)

Sukhomlinov, B.F.; Chajka, Ya.P.; Fedorovich, A.N.

1979-01-01

Using the method of electrophoresis in agar gel soluble proteins of gastric mucosa of rats were separated into 11 fractions. Proteins posessing a proteolytic (pH 1.8) and lipase (pH 7.4) activity were localized within the second and third prealbumin fractions. Soluble proteins of gastric mucosa contain glyco- and lipoproteid complexes. Exposure of rats to 1000 R of X-rays induces quantitative redistribution within the electrophoretic spectrum of soluble proteins and a considerable disturbance of the proteolytic activity of total soluble proteins throughout the entire period of observation (from 10 min to 72h)

Direct visualization of phase separation between superconducting and nematic domains in Co-doped CaFe2As2 close to a first-order phase transition

Science.gov (United States)

Fente, Antón; Correa-Orellana, Alexandre; Böhmer, Anna E.; Kreyssig, Andreas; Ran, S.; Bud'ko, Sergey L.; Canfield, Paul C.; Mompean, Federico J.; García-Hernández, Mar; Munuera, Carmen; Guillamón, Isabel; Suderow, Hermann

2018-01-01

We show that biaxial strain induces alternating tetragonal superconducting and orthorhombic nematic domains in Co-substituted CaFe2As2 . We use atomic force, magnetic force, and scanning tunneling microscopy to identify the domains and characterize their properties, finding in particular that tetragonal superconducting domains are very elongated, more than several tens of micrometers long and about 30 nm wide; have the same Tc as unstrained samples; and hold vortices in a magnetic field. Thus, biaxial strain produces a phase-separated state, where each phase is equivalent to what is found on either side of the first-order phase transition between antiferromagnetic orthorhombic and superconducting tetragonal phases found in unstrained samples when changing Co concentration. Having such alternating superconducting domains separated by normal conducting domains with sizes of the order of the coherence length opens opportunities to build Josephson junction networks or vortex pinning arrays and suggests that first-order quantum phase transitions lead to nanometric-size phase separation under the influence of strain.

Liquid-liquid phase separation in internally mixed magnesium sulfate/glutaric acid particles

Science.gov (United States)

Wu, Feng-Min; Wang, Xiao-Wei; Jing, Bo; Zhang, Yun-Hong; Ge, Mao-Fa

2018-04-01

The confocal Raman microscopy is utilized to investigate the liquid-liquid phase separation (LLPS) of mixed magnesium sulfate/glutaric acid (MgSO4/GA) droplets deposited on a hydrophobic polytetrafluoroethylene (PTFE) substrate and a hydrophilic quartz substrate. Raman spectra collected from different regions of the mixed droplets provide detailed information of component distributions for MgSO4 and GA. During the dehydration process, the MgSO4/GA mixed particles show the initial liquid-liquid phase separation between 85% and 80% relative humidity (RH) on both the hydrophobic and hydrophilic substrates. For the droplets deposited on the two substrates, the inner phase of droplets is dominated by aqueous MgSO4, which is surrounded by a rich GA organic layer due to the surface tension effects. In addition, the crystallization of GA could be observed in the organic aqueous phase while it is inhibited in the inner MgSO4 phase due to the effects of gel formation of MgSO4 at low RH. The Raman spectra reveal that with decreasing RH the morphology of the mixed droplet evolves from a uniform droplet to the structure of LLPS with the GA crystallizing in the outer layer and MgSO4 gel formed in the inner phase. These findings contribute to the further understanding of the role of interactions between inorganic salts and organic acids on the morphological evolution and environmental effects of atmospheric aerosols under ambient RH conditions.

Evaluation Of The Integrated Solubility Model, A Graded Approach For Predicting Phase Distribution In Hanford Tank Waste

Energy Technology Data Exchange (ETDEWEB)

Pierson, Kayla L.; Belsher, Jeremy D.; Seniow, Kendra R.

2012-10-19

The mission of the DOE River Protection Project (RPP) is to store, retrieve, treat and dispose of Hanford's tank waste. Waste is retrieved from the underground tanks and delivered to the Waste Treatment and Immobilization Plant (WTP). Waste is processed through a pretreatment facility where it is separated into low activity waste (LAW), which is primarily liquid, and high level waste (HLW), which is primarily solid. The LAW and HLW are sent to two different vitrification facilities and glass canisters are then disposed of onsite (for LAW) or shipped off-site (for HLW). The RPP mission is modeled by the Hanford Tank Waste Operations Simulator (HTWOS), a dynamic flowsheet simulator and mass balance model that is used for mission analysis and strategic planning. The integrated solubility model (ISM) was developed to improve the chemistry basis in HTWOS and better predict the outcome of the RPP mission. The ISM uses a graded approach to focus on the components that have the greatest impact to the mission while building the infrastructure for continued future improvement and expansion. Components in the ISM are grouped depending upon their relative solubility and impact to the RPP mission. The solubility of each group of components is characterized by sub-models of varying levels of complexity, ranging from simplified correlations to a set of Pitzer equations used for the minimization of Gibbs Energy.

Evaluation Of The Integrated Solubility Model, A Graded Approach For Predicting Phase Distribution In Hanford Tank Waste

International Nuclear Information System (INIS)

Pierson, Kayla L.; Belsher, Jeremy D.; Seniow, Kendra R.

2012-01-01

The mission of the DOE River Protection Project (RPP) is to store, retrieve, treat and dispose of Hanford's tank waste. Waste is retrieved from the underground tanks and delivered to the Waste Treatment and Immobilization Plant (WTP). Waste is processed through a pretreatment facility where it is separated into low activity waste (LAW), which is primarily liquid, and high level waste (HLW), which is primarily solid. The LAW and HLW are sent to two different vitrification facilities and glass canisters are then disposed of onsite (for LAW) or shipped off-site (for HLW). The RPP mission is modeled by the Hanford Tank Waste Operations Simulator (HTWOS), a dynamic flowsheet simulator and mass balance model that is used for mission analysis and strategic planning. The integrated solubility model (ISM) was developed to improve the chemistry basis in HTWOS and better predict the outcome of the RPP mission. The ISM uses a graded approach to focus on the components that have the greatest impact to the mission while building the infrastructure for continued future improvement and expansion. Components in the ISM are grouped depending upon their relative solubility and impact to the RPP mission. The solubility of each group of components is characterized by sub-models of varying levels of complexity, ranging from simplified correlations to a set of Pitzer equations used for the minimization of Gibbs Energy

Electrochemically Modulated Gas/Liquid Separation Technology for In Situ Resource Utilization Process Streams, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — In this phase I program MicroCell Technologies, LLC (MCT) proposes to demonstrate the feasibility of an electrochemically modulated phase separator for in situ...

Solution processing of polymer semiconductor: Insulator blends-Tailored optical properties through liquid-liquid phase separation control

KAUST Repository

Hellmann, Christoph; Treat, Neil D.; Scaccabarozzi, Alberto D.; Razzell Hollis, Joseph; Fleischli, Franziska D.; Bannock, James H.; de Mello, John; Michels, Jasper J.; Kim, Ji-Seon; Stingelin, Natalie

2014-01-01

© 2014 Wiley Periodicals, Inc. It has been demonstrated that the 0-0 absorption transition of poly(3-hexylthiophene) (P3HT) in blends with poly(ethylene oxide) (PEO) could be rationally tuned through the control of the liquid-liquid phase separation process during solution deposition. Pronounced J-like aggregation behavior, characteristic for systems of a low exciton band width, was found for blends where the most pronounced liquid-liquid phase separation occurred in solution, leading to domains of P3HT and PEO of high phase purity. Since liquid-liquid phase separation could be readily manipulated either by the solution temperature, solute concentration, or deposition temperature, to name a few parameters, our findings promise the design from the out-set of semiconductor:insulator architectures of pre-defined properties by manipulation of the interaction parameter between the solutes as well as the respective solute:solvent system using classical polymer science principles.

Solution processing of polymer semiconductor: Insulator blends-Tailored optical properties through liquid-liquid phase separation control

KAUST Repository

Hellmann, Christoph

2014-12-17

© 2014 Wiley Periodicals, Inc. It has been demonstrated that the 0-0 absorption transition of poly(3-hexylthiophene) (P3HT) in blends with poly(ethylene oxide) (PEO) could be rationally tuned through the control of the liquid-liquid phase separation process during solution deposition. Pronounced J-like aggregation behavior, characteristic for systems of a low exciton band width, was found for blends where the most pronounced liquid-liquid phase separation occurred in solution, leading to domains of P3HT and PEO of high phase purity. Since liquid-liquid phase separation could be readily manipulated either by the solution temperature, solute concentration, or deposition temperature, to name a few parameters, our findings promise the design from the out-set of semiconductor:insulator architectures of pre-defined properties by manipulation of the interaction parameter between the solutes as well as the respective solute:solvent system using classical polymer science principles.

Surface directed phase separation of semiconductor ferroelectric polymer blends and their use in non-volatile memories

NARCIS (Netherlands)

Breemen, A.J.J.M. van; Zaba, T.; Khikhlovskyi, V.; Michels, J.; Janssen, R.; Kemerink, M.; Gelinck, G.

2015-01-01

The polymer phase separation of P(VDF-TrFE):F8BT blends is studied in detail. Its morphology is key to the operation and performance of memory diodes. In this study, it is demonstrated that it is possible to direct the semiconducting domains of a phase-separating mixture of P(VDF-TrFE) and F8BT in a

The microstructure and rheology of homogeneous and phase separated gelatine gels

NARCIS (Netherlands)

Ersch, Carsten; Linden, van der Erik; Venema, Paul; Martin, Anneke

2016-01-01

The gelation of gelatine in mixtures of gelatine (type A or type B) and globular proteins (Whey Protein Isolate (WPI), Whey Protein Aggregates (WPA) and Soy Protein Isolate (SPI)) was studied with a focus on their phase separation during gelation. Confocal laser scanning microscopy, visual

Solubility behavior and biopharmaceutical classification of novel high-solubility ciprofloxacin and norfloxacin pharmaceutical derivatives.

Science.gov (United States)

Breda, Susana A; Jimenez-Kairuz, Alvaro F; Manzo, Ruben H; Olivera, María E

2009-04-17

The hydrochlorides of the 1:3 aluminum:norfloxacin and aluminum:ciprofloxacin complexes were characterized according to the Biopharmaceutics Classification System (BCS) premises in comparison with their parent compounds. The pH-solubility profiles of the complexes were experimentally determined at 25 and 37 degrees C in the range of pH 1-8 and compared to that of uncomplexed norfloxacin and ciprofloxacin. Both complexes are clearly more soluble than the antibiotics themselves, even at the lowest solubility pHs. The increase in solubility was ascribed to the species controlling solubility, which were analyzed in the solid phases at equilibrium at selected pHs. Additionally, permeability was set as low, based on data reported in the scientific literature regarding oral bioavailability, intestinal and cell cultures permeabilities and also considering the influence of stoichiometric amounts of aluminum. The complexes fulfill the BCS criterion to be classified as class 3 compounds (high solubility/low permeability). Instead, the active pharmaceutical ingredients (APIs) currently used in solid dosage forms, norfloxacin and ciprofloxacin hydrochloride, proved to be BCS class 4 (low solubility/low permeability). The solubility improvement turns the complexes as potential biowaiver candidates from the scientific point of view and may be a good way for developing more dose-efficient formulations. An immediate release tablet showing very rapid dissolution was obtained. Its dissolution profile was compared to that of the commercial ciprofloxacin hydrochloride tablets allowing to dissolution of the complete dose at a critical pH such as 6.8.

Study of solubility of some metal cyclohexane carbonates

International Nuclear Information System (INIS)

Niyazov, A.N.; Amanov, K.B.; Trapeznikova, V.F.; Kul'maksimov, A.; Kolosova, N.

1978-01-01

The solubility of calcium, magnesium, strontium, barium, cabalt, copper and aluminium cyclohexane, carbonates (CHC) in water has been studied at 25 deg C. The salt solubility has been calculated according to the metal ion concentration in saturated solutions. It has been established, that the cobalt and rare earth cyclohexane carbonates are relatively very soluble in water and have solubility products of SP > 1x10 -5 . The solubility of CHC of multivalent metals increases with the decrease of pH values. Each salt has some ''limiting'' pH value of a solution, below which it decomposes completely and can not exist in a solution in the form of solid phase

Reversible, reagentless solubility changes in phosphatidylcholine-stabilized gold nanoparticles

International Nuclear Information System (INIS)

Mackiewicz, Marilyn R; Ayres, Benjamin R; Reed, Scott M

2008-01-01

Phosphatidylcholine (PC) is a versatile ligand for synthesizing gold nanoparticles that are soluble in either organic or aqueous media. Here we report a novel route to organic-soluble, PC-stabilized gold nanoparticles that can be re-suspended in water after removal of the organic solvent. Similarly, we show that PC-stabilized gold nanoparticles synthesized in water can be re-suspended in organic solvents after complete removal of water. Without complete removal of the solvent, the nanoparticles retain their original solubility and do not phase transfer. This change in solvent preference from organic to aqueous and vice versa without the use of an additional phase transfer reagent is novel, visually striking, and of utility for synthetic modification of nanoparticles. This approach allows chemical reactions to be performed on nanoparticles in organic solvents followed by conversion of the products to water-soluble materials. A narrow distribution of PC-stabilized gold nanoparticles was obtained after phase transfer to water as characterized by UV-visible (UV-vis) spectroscopy and transmission electron microscopy (TEM), demonstrating that the narrow distribution obtained from the organic synthesis is retained after transfer to water. This method produces water-soluble nanoparticles with a narrower dispersity than is possible with direct aqueous synthesis

Improving Liquid Entry Pressure of Polyvinylidene Fluoride (PVDF Membranes by Exploiting the Role of Fabrication Parameters in Vapor-Induced Phase Separation VIPS and Non-Solvent-Induced Phase Separation (NIPS Processes

Directory of Open Access Journals (Sweden)

Faisal Abdulla AlMarzooqi

2017-02-01

Full Text Available Polyvinylidene fluoride (PVDF is a popular polymer material for making membranes for several applications, including membrane distillation (MD, via the phase inversion process. Non-solvent-induced phase separation (NIPS and vapor-induced phase separation (VIPS are applied to achieve a porous PVDF membrane with low mass-transfer resistance and high contact angle (hydrophobicity. In this work, firstly, the impacts of several preparation parameters on membrane properties using VIPS and NIPS were studied. Then, the performance of the selected membrane was assessed in a lab-scale direct-contact MD (DCMD unit. The parametric study shows that decreasing PVDF concentration while increasing both relative humidity (RH and exposure time increased the contact angle and bubble-point pore size (BP. Those trends were investigated further by varying the casting thickness. At higher casting thicknesses and longer exposure time (up to 7.5 min, contact angle (CA increased but BP significantly decreased. The latter showed a dominant trend leading to liquid entry pressure (LEP increase with thickness.

Unconventional magnetic phase separation in γ -CoV2O6

Science.gov (United States)

Shen, L.; Jellyman, E.; Forgan, E. M.; Blackburn, E.; Laver, M.; Canévet, E.; Schefer, J.; He, Z.; Itoh, M.

2017-08-01

We have explored the magnetism in the nongeometrically frustrated spin-chain system γ -CoV2O6 which possesses a complex magnetic exchange network. Our neutron diffraction patterns at low temperatures (T ≤TN=6.6 K) are best described by a model in which two magnetic phases coexist in a volume ratio 65(1) : 35(1), with each phase consisting of a single spin modulation. This model fits previous studies and our observations better than the model proposed by Lenertz et al. [J. Phys. Chem. C 118, 13981 (2014), 10.1021/jp503389c], which consisted of one phase with two spin modulations. By decreasing the temperature from TN, the minority phase of our model undergoes an incommensurate-commensurate lock-in transition at T*=5.6 K. Based on these results, we propose that phase separation is an alternative approach for degeneracy-lifting in frustrated magnets.

Phase separation in equiatomic AlCoCrFeNi high-entropy alloy

Energy Technology Data Exchange (ETDEWEB)

Manzoni, A., E-mail: anna.manzoni@helmholtz-berlin.de [Helmholtz-Zentrum Berlin, Institute of Applied Materials, D-14109 Berlin (Germany); Daoud, H.; Völkl, R.; Glatzel, U. [Metals and Alloys, University Bayreuth, Ludwig-Thoma-Strasse 36b, D-95447 Bayreuth (Germany); Wanderka, N. [Helmholtz-Zentrum Berlin, Institute of Applied Materials, D-14109 Berlin (Germany)

2013-09-15

The microstructure of the as-cast AlCoCrFeNi high entropy alloy has been investigated by transmission electron microscopy and atom probe tomography. The alloy shows a very pronounced microstructure with clearly distinguishable dendrites and interdendrites. In both regions a separation into an Al–Ni rich matrix and Cr–Fe-rich precipitates can be observed. Moreover, fluctuations of single elements within the Cr–Fe rich phase have been singled out by three dimensional atom probe measurements. The results of investigations are discussed in terms of spinodal decomposition of the alloying elements inside the Cr–Fe-rich precipitates. - Highlights: ► The Alloy separates into an Al–Ni rich matrix and Cr–Fe-rich precipitates. ► Concentration depth profiles in the Cr–Fe rich regions show opposite fluctuations. ► They have been attributed to the spinodal decomposition of Fe- and Cr-rich phases. ► The Al–Ni rich region corresponds well to the Al–Ni rich phases observed in the 6 component AlCoCrCuFeNi alloy.

Comparison of lead removal behaviors and generation of water-soluble sodium compounds in molten lead glass under a reductive atmosphere

Science.gov (United States)

Okada, Takashi; Nishimura, Fumihiro; Xu, Zhanglian; Yonezawa, Susumu

2018-06-01

We propose a method of reduction-melting at 1000 °C, using a sodium-based flux, to recover lead from cathode-ray tube funnel glass. To recover the added sodium from the treated glass, we combined a reduction-melting process with a subsequent annealing step at 700 °C, generating water-soluble sodium compounds in the molten glass. Using this combined process, this study compares lead removal behavior and the generation of water-soluble sodium compounds (sodium silicates and carbonates) in order to gain fundamental information to enhance the recovery of both lead and sodium. We find that lead removal increases with increasing melting time, whereas the generation efficiency of water-soluble sodium increases and decreases periodically. In particular, near 90% lead removal, the generation of water-soluble sodium compounds decreased sharply, increasing again with the prolongation of melting time. This is due to the different crystallization and phase separation efficiencies of water-soluble sodium in molten glass, whose structure continuously changes with lead removal. Previous studies used a melting time of 60 min in the processes. However, in this study, we observe that a melting time of 180 min enhances the water-soluble sodium generation efficiency.

Pressure-induced electronic phase separation of magnetism and superconductivity in CrAs.

Science.gov (United States)

Khasanov, Rustem; Guguchia, Zurab; Eremin, Ilya; Luetkens, Hubertus; Amato, Alex; Biswas, Pabitra K; Rüegg, Christian; Susner, Michael A; Sefat, Athena S; Zhigadlo, Nikolai D; Morenzoni, Elvezio

2015-09-08

The recent discovery of pressure (p) induced superconductivity in the binary helimagnet CrAs has raised questions on how superconductivity emerges from the magnetic state and on the mechanism of the superconducting pairing. In the present work the suppression of magnetism and the occurrence of superconductivity in CrAs were studied by means of muon spin rotation. The magnetism remains bulk up to p ≃ 3.5 kbar while its volume fraction gradually decreases with increasing pressure until it vanishes at p ≃ 7 kbar. At 3.5 kbar superconductivity abruptly appears with its maximum Tc ≃ 1.2 K which decreases upon increasing the pressure. In the intermediate pressure region (3.5 magnetic volume fractions are spatially phase separated and compete for phase volume. Our results indicate that the less conductive magnetic phase provides additional carriers (doping) to the superconducting parts of the CrAs sample thus leading to an increase of the transition temperature (Tc) and of the superfluid density (ρs). A scaling of ρs with Tc(3.2) as well as the phase separation between magnetism and superconductivity point to a conventional mechanism of the Cooper-pairing in CrAs.

Fluid Phase Separation (FPS) experiment for flight on the shuttle in a Get Away Special (GAS) canister: Design and fabrication

Science.gov (United States)

1990-01-01

The separation of fluid phases in microgravity environments is of importance to environmental control and life support systems (ECLSS) and materials processing in space. A successful fluid phase separation experiment will demonstrate a proof of concept for the separation technique and add to the knowledge base of material behavior. The phase separation experiment will contain a premixed fluid that will be exposed to a microgravity environment. After the phase separation of the compound has occurred, small samples of each of the species will be taken for analysis on Earth. By correlating the time of separation and the temperature history of the fluid, it will be possible to characterize the process. The phase separation experiment is totally self-contained, with three levels of containment on all fluids, and provides all necessary electrical power and control. The controller regulates the temperature of the fluid and controls data logging and sampling. An astronaut-activated switch will initiate the experiment and an unmaskable interrupt is provided for shutdown. The experiment has been integrated into space available on a manifested Get Away Special (GAS) experiment, CONCAP 2, part of the Consortium for Materials Complex Autonomous Payload (CAP) Program, scheduled for STS 42 in April 1991. Presented here are the design and the production of a fluid phase separation experiment for rapid implementation at low cost.

Hydrodynamic suppression of phase separation in active suspensions.

Science.gov (United States)

Matas-Navarro, Ricard; Golestanian, Ramin; Liverpool, Tanniemola B; Fielding, Suzanne M

2014-09-01

We simulate with hydrodynamics a suspension of active disks squirming through a Newtonian fluid. We explore numerically the full range of squirmer area fractions from dilute to close packed and show that "motility induced phase separation," which was recently proposed to arise generically in active matter, and which has been seen in simulations of active Brownian disks, is strongly suppressed by hydrodynamic interactions. We give an argument for why this should be the case and support it with counterpart simulations of active Brownian disks in a parameter regime that provides a closer counterpart to hydrodynamic suspensions than in previous studies.

Phase separation and magnetic ordering studied by high resolution neutron diffraction

International Nuclear Information System (INIS)

Caspi, E.N.; Melamud, M.; Pinto, H.; Shaked, H.; Chmaissem, O.; Jorgensen, J.D.; Short, S.

1999-01-01

Complete text of publication follows. In a previous work on the (U 1-x Nd x )Co 2 Ge 2 system, two magnetic transitions were observed in the temperature dependencies of the magnetic susceptibility and in the intensity of the magnetic reflections in neutron diffraction [1]. Because of insufficient resolution, it was not clear whether this is due to clustering or phase separation. In both cases the U-rich regions are expected to order magnetically at higher temperature than the U-poor ones, resulting in two magnetic transitions. In order to resolve this question a temperature dependent TOF neutron diffraction of the x = 0.25 compound has been performed on the SEPD at Argonne's IPNS [2]. The temperature dependent diffractograms were refined by the Rietveld method. It was found that the compound separates into two phases: x = 0.4 (55 wt%) and x = 0.1 (45 wt%). The temperature dependence of the magnetic moment was obtained for each phase, with the transition temperatures: T N (x=0.4) = 130 K, and T N (x=0.1) = 165 K. (author) [1] E. Caspi et al., Phys. Rev. B, 57 (198) 449.; [2] J.D. Jorgensen et al., J. Appl. Cryst. 22 (1989) 321

Enthalpy-entropy compensation for the solubility of drugs in solvent mixtures: paracetamol, acetanilide, and nalidixic acid in dioxane-water.

Science.gov (United States)

Bustamante, P; Romero, S; Pena, A; Escalera, B; Reillo, A

1998-12-01

In earlier work, a nonlinear enthalpy-entropy compensation was observed for the solubility of phenacetin in dioxane-water mixtures. This effect had not been earlier reported for the solubility of drugs in solvent mixtures. To gain insight into the compensation effect, the behavior of the apparent thermodynamic magnitudes for the solubility of paracetamol, acetanilide, and nalidixic acid is studied in this work. The solubility of these drugs was measured at several temperatures in dioxane-water mixtures. DSC analysis was performed on the original powders and on the solid phases after equilibration with the solvent mixture. The thermal properties of the solid phases did not show significant changes. The three drugs display a solubility maximum against the cosolvent ratio. The solubility peaks of acetanilide and nalidixic acid shift to a more polar region at the higher temperatures. Nonlinear van't Hoff plots were observed for nalidixic acid whereas acetanilide and paracetamol show linear behavior at the temperature range studied. The apparent enthalpies of solution are endothermic going through a maximum at 50% dioxane. Two different mechanisms, entropy and enthalpy, are suggested to be the driving forces that increase the solubility of the three drugs. Solubility is entropy controlled at the water-rich region (0-50% dioxane) and enthalpy controlled at the dioxane-rich region (50-100% dioxane). The enthalpy-entropy compensation analysis also suggests that two different mechanisms, dependent on cosolvent ratio, are involved in the solubility enhancement of the three drugs. The plots of deltaH versus deltaG are nonlinear, and the slope changes from positive to negative above 50% dioxane. The compensation effect for the thermodynamic magnitudes of transfer from water to the aqueous mixtures can be described by a common empirical nonlinear relationship, with the exception of paracetamol, which follows a separate linear relationship at dioxane ratios above 50%. The

Development of clinical dosage forms for a poorly water-soluble drug II: formulation and characterization of a novel solid microemulsion preconcentrate system for oral delivery of a poorly water-soluble drug.

Science.gov (United States)

Li, Ping; Hynes, Sara R; Haefele, Thomas F; Pudipeddi, Madhu; Royce, Alan E; Serajuddin, Abu T M

2009-05-01

The solution of a poorly water-soluble drug in a liquid lipid-surfactant mixture, which served as a microemulsion preconcentrate, was converted into a solid form by incorporating it in a solid polyethylene glycol (PEG) matrix. The solid microemulsion preconcentrates thus formed consisted of Capmul PG8 (propylene glycol monocaprylate) as oil, Cremophor EL (polyoxyl 35 castor oil) as surfactant, and hydrophilic polymer PEG 3350 as solid matrix. The drug (aqueous solubility: 0.17 microg/mL at pH 1-8 and 25 degrees C) was dissolved in a melt of the mixture at 65-70 degrees C and then the hot solution was filled into hard gelatin capsules; the liquid gradually solidified upon cooling below 55 degrees C. The solid system was characterized by differential scanning calorimetry (DSC), scanning electron microscopy (SEM), confocal Raman microscopy (CRM), and the dispersion testing in water. It was confirmed that a solid microemulsion preconcentrate is a two-phase system, where clusters of crystalline PEG 3350 formed the solid structure (m.p. 55-60 degrees C) and the liquid microemulsion preconcentrate dispersed in between PEG 3350 crystals as a separate phase. The drug remained dissolved in the liquid phase. In vitro release testing showed that the preconcentrate dispersed readily in water forming a microemulsion with the drug dissolved in the oil particles (PEG 3350 did not interfere with the process of self-microemulsification.

Conducting polymer networks synthesized by photopolymerization-induced phase separation

Science.gov (United States)

Yamashita, Yuki; Komori, Kana; Murata, Tasuku; Nakanishi, Hideyuki; Norisuye, Tomohisa; Yamao, Takeshi; Tran-Cong-Miyata, Qui

2018-03-01

Polymer mixtures composed of double networks of a polystyrene derivative (PSAF) and poly(methyl methacrylate) (PMMA) were alternatively synthesized by using ultraviolet (UV) and visible (Vis) light. The PSAF networks were generated by UV irradiation to photodimerize the anthracene (A) moieties labeled on the PSAF chains, whereas PMMA networks were produced by photopolymerization of methyl methacrylate (MMA) monomer and the cross-link reaction using ethylene glycol dimethacrylate (EGDMA) under Vis light irradiation. It was found that phase separation process of these networks can be independently induced and promptly controlled by using UV and Vis light. The characteristic length scale distribution of the resulting co-continuous morphology can be well regulated by the UV and Vis light intensity. In order to confirm and utilize the connectivity of the bicontinuous morphology observed by confocal microscopy, a very small amount, 0.1 wt%, of multi-walled carbon nanotubes (MWCNTs) was introduced into the mixture and the current-voltage (I-V) relationship was subsequently examined. Preliminary data show that MWCNTs are preferentially dispersed in the PSAF-rich continuous domains and the whole mixture became electrically conducting, confirming the connectivity of the observed bi-continuous morphology. The experimental data obtained in this study reveal a promising method to design various scaffolds for conducting soft matter taking advantages of photopolymerization-induced phase separation.

Operation of a separated-type x-ray interferometer for phase-contrast x-ray imaging

Science.gov (United States)

Yoneyama, Akio; Momose, Atsushi; Seya, Eiichi; Hirano, Keiichi; Takeda, Tohoru; Itai, Yuji

1999-12-01

Aiming at large-area phase-contrast x-ray imaging, a separated-type x-ray interferometer system was designed and developed to produce 25×20 mm interference patterns. The skew-symmetric optical system was adopted because of the feasibility of alignment. The rotation between the separated crystal blocks was controlled within a drift of 0.06 nrad using a feedback positioning system. This interferometer generated a 25×15 mm interference pattern with 0.07 nm synchrotron x-rays. A slice of a rabbit's kidney was observed, and its tubular structure could be revealed in a measured phase map.

Variation in pH of Model Secondary Organic Aerosol during Liquid-Liquid Phase Separation.

Science.gov (United States)

Dallemagne, Magda A; Huang, Xiau Ya; Eddingsaas, Nathan C

2016-05-12

The majority of atmospheric aerosols consist of both organic and inorganic components. At intermediate relative humidity (RH), atmospheric aerosol can undergo liquid-liquid phase separation (LLPS) in which the organic and inorganic fractions segregate from each other. We have extended the study of LLPS to the effect that phase separation has on the pH of the overall aerosols and the pH of the individual phases. Using confocal microscopy and pH sensitive dyes, the pH of internally mixed model aerosols consisting of polyethylene glycol 400 and ammonium sulfate as well as the pH of the organic fraction during LLPS have been directly measured. During LLPS, the pH of the organic fraction was observed to increase to 4.2 ± 0.2 from 3.8 ± 0.1 under high RH when the aerosol was internally mixed. In addition, the high spatial resolution of the confocal microscope allowed us to characterize the composition of each of the phases, and we have observed that during LLPS the organic shell still contains large quantities of water and should be characterized as an aqueous organic-rich phase rather than simply an organic phase.

Phase equilibria in chemical reactive fluid mixtures

International Nuclear Information System (INIS)

Maurer, Gerd

2011-01-01

Downstream processing is a major part of nearly all processes in the chemical industries. Most separation processes in the chemical (and related) industries for fluid mixtures are based on phase equilibrium phenomena. The majority of separation processes can be modelled assuming that chemical reactions are of no (or very minor) importance, i.e., assuming that the overall speciation remains unchanged during a separation process. However, there are also a large number of industrially important processes where the thermodynamic properties are influenced by chemical reactions. The phase equilibrium of chemical reactive mixtures has been a major research area of the author's group over nearly 40 years. In this contribution, three examples from that research are discussed. The first example deals with the vapour phase dimerisation of carboxylic acids and its consequences on phase equilibrium phenomena and phase equilibrium predictions. The second example deals with the solubility of sour gases (e.g., carbon dioxide and sulfur dioxide) in aqueous solutions of ammonia. That topic has been of interest for many years, e.g., in relation with the gasification and liquefaction of coal and, more recently, with the removal of carbon dioxide from flue gas in the 'chilled ammonia process'. The third example deals with phase equilibrium phenomena in aqueous solutions of polyelectrolytes. It deals with the phenomenon of 'counter ion condensation' and methods to model the Gibbs free energy of such solutions.

Rapid determination of water- and fat-soluble vitamins with microemulsion electrokinetic chromatography.

Science.gov (United States)

Yin, Changna; Cao, Yuhua; Ding, Shaodong; Wang, Yun

2008-06-06

A rapid, reliable and reproducible method based on microemulsion electrokinetic chromatography (MEEKC) for simultaneous determination of 13 kinds of water- and fat-soluble vitamins has been developed in this work. A novel microemulsion system consisting of 1.2% (w/w) sodium lauryl sulphate (SDS), 21% (v/v) 1-butanol, 18% (v/v) acetonitrile, 0.8% (w/w) n-hexane, 20mM borax buffer (pH 8.7) was applied to improve selectivity and efficiency, as well as shorten analysis time. The composition of microemulsion used as the MEEKC running buffer was investigated thoroughly to obtain stable separation medium, as well as the optimum determination conditions. Acetonitrile as the organic solvent modifier, pH of the running buffer and 1-butanol as the co-surfactant played the most important roles for the separation of the fat-soluble vitamins, water-soluble vitamins and stabilization of system, respectively. The 13 water- and fat-soluble vitamins were baseline separated within 30 min. The system was applied to determine water- and fat-soluble vitamins in commercial multivitamin pharmaceutical formulation, good accuracy and precision were obtained with recoveries between 97% and 105%, relative standard derivations (RSDs) less than 1.8% except vitamin C, and acceptable quantitative results corresponding to label claim.

Integration of carboxyl modified magnetic particles and aqueous two-phase extraction for selective separation of proteins.

Science.gov (United States)

Gai, Qingqing; Qu, Feng; Zhang, Tao; Zhang, Yukui

2011-07-15

Both of the magnetic particle adsorption and aqueous two-phase extraction (ATPE) were simple, fast and low-cost method for protein separation. Selective proteins adsorption by carboxyl modified magnetic particles was investigated according to protein isoelectric point, solution pH and ionic strength. Aqueous two-phase system of PEG/sulphate exhibited selective separation and extraction for proteins before and after magnetic adsorption. The two combination ways, magnetic adsorption followed by ATPE and ATPE followed by magnetic adsorption, for the separation of proteins mixture of lysozyme, bovine serum albumin, trypsin, cytochrome C and myloglobin were discussed and compared. The way of magnetic adsorption followed by ATPE was also applied to human serum separation. Copyright © 2011 Elsevier B.V. All rights reserved.

Solubility and hydrolysis of Np(V) in dilute to concentrated alkaline NaCl solutions. Formation of Na-Np(V)-OH solid phases at 22 C

Energy Technology Data Exchange (ETDEWEB)

Petrov, Vladimir G. [Lomonosov Moscow State Univ. (Russian Federation). Dept. of Chemistry; Fellhauer, David; Gaona, Xavier; Dardenne, Kathy; Rothe, Joerg; Altmaier, Marcus [Karlsruhe Institute of Technology (Germany). Inst. for Nuclear Waste Disposal; Kalmykov, Stepan N. [Lomonosov Moscow State Univ. (Russian Federation). Dept. of Chemistry; NRC Kurchatov Institute, Moscow (Russian Federation)

2017-03-01

The solubility of Np(V) was investigated at T=22±2 C in alkaline NaCl solutions of different ionic strength (0.1-5.0 M). The solid phases controlling the solubility at different -log{sub 10} m{sub H{sup +}}(pH{sub m}) and NaCl concentration were characterized by XRD, quantitative chemical analysis, SEM-EDS and XAFS (both XANES and EXAFS). Aqueous phases in equilibrium with Np(V) solids were investigated for selected samples within 8.9≤pH{sub m}≤10.3 by UV-vis/NIR absorption spectroscopy. In 0.1 M NaCl, the experimental solubility of the initial greenish NpO{sub 2}OH(am) solid phase is in good agreement with previous results obtained in NaClO{sub 4} solutions, and is consistent with model calculations for fresh NpO{sub 2}OH(am) using the thermodynamic data selection in NEA-TDB. Below pH{sub m}∝11.5 and for all NaCl concentrations studied, Np concentration in equilibrium with the solid phase remained constant during the timeframe of this study (∝2 years). This observation is in contrast to the aging of the initial NpO{sub 2}OH(am) into a more crystalline modification with the same stoichiometry, NpO{sub 2}OH(am, aged), as reported in previous studies for concentrated NaClO{sub 4} and NaCl. Instead, the greenish NpO{sub 2}OH(am) transforms into a white solid phase in those systems with [NaCl]≥1.0 M and pH{sub m}≥11.5, and into two different pinkish phases above pH{sub m}∝13.2. The solid phase transformation is accompanied by a drop in Np solubility of 0.5-2 log{sub 10}-units (depending upon NaCl concentration). XANES analyses of green, white and pink phases confirm the predominance of Np(V) in all cases. Quantitative chemical analysis shows the incorporation of Na{sup +} in the original NpO{sub 2}OH(am) material, with Na:Np ≤ 0.3 for the greenish solids and 0.8 ≤ Na:Np ≤ 1.6 for the white and pinkish phases. XRD data confirms the amorphous character of the greenish phase, whereas white and pink solids show well-defined but discrepant XRD patterns

Luminescence of MnS in glasses: spectroscopic probe for the study of thermal phase separation

Energy Technology Data Exchange (ETDEWEB)

Menassa, P E

1984-01-01

A new approach for studying thermal phase separation in sodium borosilicate glasses using MnS as a luminescent probe is investigated. Seventy-one samples of glasses activated by MnS inside and around the Na2O.B2O3.SiO2 miscibility gaps were prepared. These samples were then phase separated by dry thermal treatment. It is shown that on addition of MnO, the ternary Na2O.B2O3.SiO2 system behaved like other quaternary systems of the type X2O.MO.B2O3.SiO2 (X = Na, K; M = Mg, Ca, Ba, Zn). Scanning electron microscopy and X-ray microanalysis demonstrated that manganese concentrates preferentially in the boron-rich phase. This, analysis, in conjuction with a comparison of MnS emission spectra of upheated and heat treated glasses shows that the glasses are submicroscopically phase separated when prepared. The decay-time analysis of MnS luminescence indicates that the low energy emission band arises from MnS in the boron-rich phase while the high energy emission is due to MnS in the silica-rich phase. The difference in the crystal field parameters obtained from the excitation spectra of the two emission bands shows that the high energy emission band is from MnS in tetrahedral sites while the low energy emission band is from MnS in an octahedral environment.

Reversed-Phase UHPLC Enantiomeric Separation of Rasagiline Salts Using a Chiralpak® AGP Column

Directory of Open Access Journals (Sweden)

Nagarajan Balaji

2017-07-01

Full Text Available We report the first rapid ultra-high performance liquid chromatographic (UHPLC enantiomeric reversed-phase separation of rasagiline mesylate and its tartrate salts using a Chiralpak® AGP column (50 mm × 2.1 mm, 5 μm as a stationary phase. This method was developed as an alternative to the usage of previously reported normal-phase chiral LC columns for isomer separation. Our method is based on an isocratic approach using a mixture of ammonium acetate and isopropyl alcohol (90:10, v/v as the mobile phase (0.6 mL/min flow rate. The detection limit (at a detection wavelength of 210 nm and quantification limit for the rasagiline enantiomers were 0.06 and 0.2 μg/mL, respectively. This method is compatible with the UHPLC-MS technique. The successful separation of rasagiline and its enantiomer was confirmed by determining the corresponding specific optical rotation values. Our method will be applicable for detecting rasagiline enantiomers during the control of manufacturing processes, and for use in rapid analysis for quality control in pharmaceutical industry to obtain optically pure pharmaceutical substances. This method was validated in terms of its precision, limit of detection, limit of quantification, linearity, accuracy, robustness, ruggedness, specificity, forced degradation, and solution stability, according to International Council on Harmonization Validation Guidelines Q2 (R1.

Mesoporous calcium carbonate as a phase stabilizer of amorphous celecoxib--an approach to increase the bioavailability of poorly soluble pharmaceutical substances.

Science.gov (United States)

Forsgren, Johan; Andersson, Mattias; Nilsson, Peter; Mihranyan, Albert

2013-11-01

The bioavailability of crystalline pharmaceutical substances is often limited by their poor aqueous solubility but it can be improved by formulating the active substance in the amorphous state that is featured with a higher apparent solubility. Although the possibility of stabilizing amorphous drugs inside nano-sized pores of carbon nanotubes and ordered mesoporous silica has been shown, no conventional pharmaceutical excipients have so far been shown to possess this property. This study demonstrates the potential of using CaCO3 , a widely used excipient in oral drug formulations, to stabilize the amorphous state of active pharmaceutical ingredients, in particular celecoxib. After incorporation of celecoxib in the vaterite particles, a five to sixfold enhancement in apparent solubility of celecoxib is achieved due to pore-induced amorphization. To eliminate the possibility of uncontrolled phase transitions, the vaterite particles are stored in an inert atmosphere at 5 °C throughout the study. Also, to demonstrate that the amorphization effect is indeed associated with vaterite mesopores, accelerated stress conditions of 100% relative humidity are employed to impose transition from mesoporous vaterite to an essentially non-porous aragonite phase of CaCO3 , which shows only limited amorphization ability. Further, an improvement in solubility is also confirmed for ketoconazole when formulated with the mesoporous vaterite. Synthesis of the carrier particles and the incorporation of the active substances are carried out simultaneously in a one-step procedure, enabling easy fabrication. These results represent a promising approach to achieve enhanced bioavailability in new formulations of Type II BCS drugs. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effects of polarity, hydrophobicity, and density of ionic liquids on cellulose solubility.

Science.gov (United States)

Abe, Mitsuru; Kuroda, Kosuke; Sato, Daiki; Kunimura, Haruhito; Ohno, Hiroyuki

2015-12-28

We have synthesised novel ionic liquids (ILs) to show both cellulose dissolution ability and LCST-type phase transition after mixing with water. To realise both polar and hydrophobic properties, tetraalkylphosphonium cations and a series of carboxylate anions were employed to assume hydrophobic and highly polar properties, respectively. Effects of their alkyl chain length on the water compatibility and cellulose solubility of the corresponding ILs were systematically examined. We succeeded in synthesising novel ILs which dissolve cellulose and separable with water at moderate temperature. Through the present study, we have clarified that not only polarity but also density of ILs is an important factor in designing the ILs for cellulose dissolution.

Separation of Aeruginosin-865 from Cultivated Soil Cyanobacterium (Nostoc sp.) by Centrifugal Partition Chromatography combined with Gel Permeation Chromatography.

Science.gov (United States)

Cheel, José; Minceva, Mirjana; Urajová, Petra; Aslam, Rabya; Hrouzek, Pavel; Kopecký, Jiří

2015-10-01

Aeruginosin-865 was isolated from cultivated soil cyanobacteria using a combination of centrifugal partition chromatography (CPC) and gel permeation chromatography. The solubility of Aer-865 in different solvents was evaluated using the conductor-like screening model for real solvents (COSMO-RS). The CPC separation was performed in descending mode with a biphasic solvent system composed of water-n-BuOH-acetic acid (5:4:1, v/v/v). The upper phase was used as a stationary phase, whereas the lower phase was employed as a mobile phase at a flow rate of 10 mL/min. The revolution speed and temperature of the separation column were 1700 rpm and 25 degrees C, respectively. Preparative CPC separation followed by gel permeation chromatography was performed on 50 mg of crude extract yielding Aer-865 (3.5 mg), with a purity over 95% as determined by HPLC. The chemical identity of the isolated compound was confirmed by comparing its spectroscopic data (UV, HRESI-MS, HRESI-MS/MS) with those of an authentic standard and data available in the literature.

Sibutramine characterization and solubility, a theoretical study

Science.gov (United States)

Aceves-Hernández, Juan M.; Nicolás Vázquez, Inés; Hinojosa-Torres, Jaime; Penieres Carrillo, Guillermo; Arroyo Razo, Gabriel; Miranda Ruvalcaba, René

2013-04-01

Solubility data from sibutramine (SBA) in a family of alcohols were obtained at different temperatures. Sibutramine was characterized by using thermal analysis and X-ray diffraction technique. Solubility data were obtained by the saturation method. The van't Hoff equation was used to obtain the theoretical solubility values and the ideal solvent activity coefficient. No polymorphic phenomena were found from the X-ray diffraction analysis, even though this compound is a racemic mixture of (+) and (-) enantiomers. Theoretical calculations showed that the polarisable continuum model was able to reproduce the solubility and stability of sibutramine molecule in gas phase, water and a family of alcohols at B3LYP/6-311++G (d,p) level of theory. Dielectric constant, dipolar moment and solubility in water values as physical parameters were used in those theoretical calculations for explaining that behavior. Experimental and theoretical results were compared and good agreement was obtained. Sibutramine solubility increased from methanol to 1-octanol in theoretical and experimental results.

Modeling the gas-particle partitioning of secondary organic aerosol: the importance of liquid-liquid phase separation

Directory of Open Access Journals (Sweden)

A. Zuend

2012-05-01

Full Text Available The partitioning of semivolatile organic compounds between the gas phase and aerosol particles is an important source of secondary organic aerosol (SOA. Gas-particle partitioning of organic and inorganic species is influenced by the physical state and water content of aerosols, and therefore ambient relative humidity (RH, as well as temperature and organic loading levels. We introduce a novel combination of the thermodynamic models AIOMFAC (for liquid mixture non-ideality and EVAPORATION (for pure compound vapor pressures with oxidation product information from the Master Chemical Mechanism (MCM for the computation of gas-particle partitioning of organic compounds and water. The presence and impact of a liquid-liquid phase separation in the condensed phase is calculated as a function of variations in relative humidity, organic loading levels, and associated changes in aerosol composition. We show that a complex system of water, ammonium sulfate, and SOA from the ozonolysis of α-pinene exhibits liquid-liquid phase separation over a wide range of relative humidities (simulated from 30% to 99% RH. Since fully coupled phase separation and gas-particle partitioning calculations are computationally expensive, several simplified model approaches are tested with regard to computational costs and accuracy of predictions compared to the benchmark calculation. It is shown that forcing a liquid one-phase aerosol with or without consideration of non-ideal mixing bears the potential for vastly incorrect partitioning predictions. Assuming an ideal mixture leads to substantial overestimation of the particulate organic mass, by more than 100% at RH values of 80% and by more than 200% at RH values of 95%. Moreover, the simplified one-phase cases stress two key points for accurate gas-particle partitioning calculations: (1 non-ideality in the condensed phase needs to be considered and (2 liquid-liquid phase separation is a consequence of considerable deviations

Phase separation in short-chain lecithin/gel-state long-chain lecithin aggregates

International Nuclear Information System (INIS)

Bian, J.; Roberts, M.F.

1990-01-01

Small bilayer particles for spontaneously from gel-state long-chain phospholipids such as dipalmitoylphosphatidylcholine and 0.2 mol fraction short-chain lecithins (e.g., diheptanoylphosphatidylcholine). When the particles are incubed at temperatures greater than the T m of the long-chain phosphatidylcholine (PC), the particles rapidly fuse (from 90-angstrom to ≥ 5,000-angstrom radius); this transition is reversible. A possible explanation for this behavior involves patching or phase separation of the short-chain component within the gel-state particle and randomization of both lipid species above T m . Differential scanning calorimetry, 1 H T 1 values of proteodiheptanoyl-PC in diheptanoyl-PC-d 26 /dipalmitoyl-PC-d 62 matrices of varying deuterium content, solid-state 2 H NMR spectroscopy as a function of temperature, and fluorescence pyrene excimer-to-monomer ratios as a function of mole fraction diheptanoyl-PC provide evidence that such phase separation must occur. These results are used to construct a phase diagram for the diheptanoyl-PC/dipalmitoyl-PC system, to propose detailed geometric models for the different lipid particles involved, and to understand phospholipase kinetics toward the different aggregates

Magnetoresistive memory in phase-separated La0.5Ca0.5MnO3

Energy Technology Data Exchange (ETDEWEB)

Sacanell, J. [Departamento de Fisica, Unidad de Actividad Fisica-Centro Atomico de Constituyentes, CNEA, Av. Gral. Paz 1499, San Martin 1650, Pcia. de Buenos Aires (Argentina)]. E-mail: sacanell@cnea.gov.ar; Parisi, F. [Departamento de Fisica, Unidad de Actividad Fisica-Centro Atomico de Constituyentes, CNEA, Av. Gral. Paz 1499, San Martin 1650, Pcia. de Buenos Aires (Argentina); Levy, P. [Departamento de Fisica, Unidad de Actividad Fisica-Centro Atomico de Constituyentes, CNEA, Av. Gral. Paz 1499, San Martin 1650, Pcia. de Buenos Aires (Argentina); Ghivelder, L. [Instituto de Fisica, UFRJ, Rio de Janeiro (Brazil)

2004-12-31

We have studied a non-volatile memory effect in the mixed valent compound La0.5Ca0.5MnO3 induced by magnetic field (H). In a previous work (Phys. Rev. B 65 (2002) 104403), it has been shown that the response of this system upon application of H strongly depends on the temperature range, related to three well-differentiated regimes of phase separation occurring below 220K. In this work we compare memory capabilities of the compound, determined following two different experimental procedures for applying H, namely zero-field cooling and field cooling the sample. These results are analyzed and discussed within the scenario of phase separation.

Magnetoresistive memory in phase-separated La0.5Ca0.5MnO3

International Nuclear Information System (INIS)

Sacanell, J.; Parisi, F.; Levy, P.; Ghivelder, L.

2004-01-01

We have studied a non-volatile memory effect in the mixed valent compound La0.5Ca0.5MnO3 induced by magnetic field (H). In a previous work (Phys. Rev. B 65 (2002) 104403), it has been shown that the response of this system upon application of H strongly depends on the temperature range, related to three well-differentiated regimes of phase separation occurring below 220K. In this work we compare memory capabilities of the compound, determined following two different experimental procedures for applying H, namely zero-field cooling and field cooling the sample. These results are analyzed and discussed within the scenario of phase separation

Dynamical mean-field theory and weakly non-linear analysis for the phase separation of active Brownian particles

Energy Technology Data Exchange (ETDEWEB)

Speck, Thomas [Institut für Physik, Johannes Gutenberg-Universität Mainz, Staudingerweg 7-9, 55128 Mainz (Germany); Menzel, Andreas M.; Bialké, Julian; Löwen, Hartmut [Institut für Theoretische Physik II, Heinrich-Heine-Universität, D-40225 Düsseldorf (Germany)

2015-06-14

Recently, we have derived an effective Cahn-Hilliard equation for the phase separation dynamics of active Brownian particles by performing a weakly non-linear analysis of the effective hydrodynamic equations for density and polarization [Speck et al., Phys. Rev. Lett. 112, 218304 (2014)]. Here, we develop and explore this strategy in more detail and show explicitly how to get to such a large-scale, mean-field description starting from the microscopic dynamics. The effective free energy emerging from this approach has the form of a conventional Ginzburg-Landau function. On the coarsest scale, our results thus agree with the mapping of active phase separation onto that of passive fluids with attractive interactions through a global effective free energy (motility-induced phase transition). Particular attention is paid to the square-gradient term necessary for the phase separation kinetics. We finally discuss results from numerical simulations corroborating the analytical results.

Enrichment of dynamic chromosomal crosslinks drive phase separation of the nucleolus.

Science.gov (United States)

Hult, Caitlin; Adalsteinsson, David; Vasquez, Paula A; Lawrimore, Josh; Bennett, Maggie; York, Alyssa; Cook, Diana; Yeh, Elaine; Forest, Mark Gregory; Bloom, Kerry

2017-11-02

Regions of highly repetitive DNA, such as those found in the nucleolus, show a self-organization that is marked by spatial segregation and frequent self-interaction. The mechanisms that underlie the sequestration of these sub-domains are largely unknown. Using a stochastic, bead-spring representation of chromatin in budding yeast, we find enrichment of protein-mediated, dynamic chromosomal cross-links recapitulates the segregation, morphology and self-interaction of the nucleolus. Rates and enrichment of dynamic crosslinking have profound consequences on domain morphology. Our model demonstrates the nucleolus is phase separated from other chromatin in the nucleus and predicts that multiple rDNA loci will form a single nucleolus independent of their location within the genome. Fluorescent labeling of budding yeast nucleoli with CDC14-GFP revealed that a split rDNA locus indeed forms a single nucleolus. We propose that nuclear sub-domains, such as the nucleolus, result from phase separations within the nucleus, which are driven by the enrichment of protein-mediated, dynamic chromosomal crosslinks. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

HIGH PRESSURE PHASE EQUILIBRIUM: PREDICTION OF ESSENTIAL OIL SOLUBILITY

Directory of Open Access Journals (Sweden)

Lúcio CARDOZO-FILHO

1997-12-01

Full Text Available This work describes a method to predict the solubility of essential oils in supercritical carbon dioxide. The method is based on the formulation proposed in 1979 by Asselineau, Bogdanic and Vidal. The Peng-Robinson and Soave-Redlich-Kwong cubic equations of state were used with the van der Waals mixing rules with two interaction parameters. Method validation was accomplished calculating orange essential oil solubility in pressurized carbon dioxide. The solubility of orange essential oil in carbon dioxide calculated at 308.15 K for pressures of 50 to 70 bar varied from 1.7± 0.1 to 3.6± 0.1 mg/g. For same the range of conditions, experimental solubility varied from 1.7± 0.1 to 3.6± 0.1 mg/g. Predicted values were not very sensitive to initial oil composition.Este trabalho descreve uma metodologia para o cálculo da solubilidade de óleos essenciais em dióxido de carbono a altas pressões baseada na formulação proposta em 1979 por Asselineau, Bogdanic e Vidal. Foram utilizadas as equações cúbicas de estado de Peng-Robinson e Soave-Redlich-Kwong com regras de mistura de van der Waals com dois parâmetros de interação. O cálculo da solubilidade do óleo essencial de laranja em dióxido de carbono pressurizado foi usado para validação do método. A solubilidade calculada a 308,15 K para pressões entre 50 e 70 bar variou entre 1,5 e 4,1 mg/g. Valores experimentais para as mesmas condições variam entre 1,7± 0.1 a 3,6± 0.1 mg/g. Os valores preditos não são muito sensíveis à composição inicial do óleo essencial.

Renormalization-group study of superfluidity and phase separation of helium mixtures immersed in a disordered porous medium

International Nuclear Information System (INIS)

Lopatnikova, A.; Berker, A.N.

1997-01-01

Superfluidity and phase separation in 3 He- 4 He mixtures immersed in aerogel are studied by renormalization-group theory. The quenched disorder imposed by aerogel, both at the atomic level and at the geometric level, is included. The calculation is conducted via the coupled renormalization-group mappings, near and away from aerogel, of the quenched probability distributions of random interactions. Random-bond effects on the onset of superfluidity and random-field effects on superfluid-superfluid phase separation are seen. The quenched randomness causes the λ line of second-order phase transitions of superfluidity onset to reach zero temperature, in agreement with general predictions and experiments. The effects of the atomic and geometric randomness of aerogel are investigated separately and jointly. copyright 1997 The American Physical Society

Simultaneous Design of Ionic Liquids and Azeotropic Separation Processes

DEFF Research Database (Denmark)

Roughton, Brock C.; White, John; Camarda, Kyle V.

2011-01-01

A methodology for the design of azeotrope separation processes using ionic liquids as entrainers is outlined. A Hildebrand solubility parameter group contribution model has been developed to screen for or design an ionic liquid entrainer that is soluble with the azeotropic components. Using the b...... % [BMPy][BF4] added. The driving force concept is used to design an extractive distillation process that minimizes energy inputs. The methodology given can be expanded to the use of ionic liquids as entrainers in any azeotropic system of interest.......A methodology for the design of azeotrope separation processes using ionic liquids as entrainers is outlined. A Hildebrand solubility parameter group contribution model has been developed to screen for or design an ionic liquid entrainer that is soluble with the azeotropic components. Using...

Managing Zirconium Chemistry and Phase Compatibility in Combined Process Separations for Minor Actinide Partitioning

Energy Technology Data Exchange (ETDEWEB)

Wall, Nathalie [Washington State Univ., Pullman, WA (United States); Nash, Ken [Washington State Univ., Pullman, WA (United States); Martin, Leigh [Washington State Univ., Pullman, WA (United States)

2017-03-17

In response to the NEUP Program Supporting Fuel Cycle R&D Separations and Waste Forms call DEFOA- 0000799, this report describes the results of an R&D project focusing on streamlining separation processes for advanced fuel cycles. An example of such a process relevant to the U.S. DOE FCR&D program would be one combining the functions of the TRUEX process for partitioning of lanthanides and minor actinides from PUREX(UREX) raffinates with that of the TALSPEAK process for separating transplutonium actinides from fission product lanthanides. A fully-developed PUREX(UREX)/TRUEX/TALSPEAK suite would generate actinides as product(s) for reuse (or transmutation) and fission products as waste. As standalone, consecutive unit-operations, TRUEX and TALSPEAK employ different extractant solutions (solvating (CMPO, octyl(phenyl)-N,Ndiisobutylcarbamoylmethylphosphine oxide) vs. cation exchanging (HDEHP, di-2(ethyl)hexylphosphoric acid) extractants), and distinct aqueous phases (2-4 M HNO₃ vs. concentrated pH 3.5 carboxylic acid buffers containing actinide selective chelating agents). The separate processes may also operate with different phase transfer kinetic constraints. Experience teaches (and it has been demonstrated at the lab scale) that, with proper control, multiple process separation systems can operate successfully. However, it is also recognized that considerable economies of scale could be achieved if multiple operations could be merged into a single process based on a combined extractant solvent. The task of accountability of nuclear materials through the process(es) also becomes more robust with fewer steps, providing that the processes can be accurately modeled. Work is underway in the U.S. and Europe on developing several new options for combined processes (TRUSPEAK, ALSEP, SANEX, GANEX, ExAm are examples). There are unique challenges associated with the operation of such processes, some relating to organic phase chemistry, others arising from the

Separations chemistry

International Nuclear Information System (INIS)

Anon.

1977-01-01

Infrared spectra of Pu(IV) polymer show effects of CO 2 adsorption and of aging. Uv light (300 nm) increases the rate of reduction of PuO 2 2+ and Pu 4+ to Pu 3+ and the Pu--U separation factor using TBP. Distribution ratios for Zr and Hf between Dowex 50W--X8 resin and H 2 SO 4 solutions were found to decrease sharply with H 2 SO 4 content. Octylphenyl acid phosphate, a mixture of monooctylphenyl and dioctylphenyl phosphoric acids, is being studied for U recovery from wet-process phosphoric acid. A study of HNO 3 leaching of Ra from U ores was completed. Effects of particle size of the packed bed on the dispersion of the boundary of the miscible phase used in oil recovery are being studied. Effects of sulfonates on toluene--n-butanol--water phase relations were determined, as were the effects of salts and solutes on the max water content of 1:1 toluene--alcohol solutions. A study was begun of hydrocarbon solubility in water--surfactant--alcohol. The mechanism of the formation of hydrous ZrO 2 --polyacrylate membranes and their use for sulfate rejection were studied. Salt rejection through hyperfiltration by clay membranes (bentonite and kaolin) was also investigated. Preliminary results are given for hyperfiltration of wood-pulping wastes by ZrO 2 membranes. 13 figures

Anisotropic properties of phase separation in two-component dipolar Bose-Einstein condensates

Science.gov (United States)

Wang, Wei; Li, Jinbin

2018-03-01

Using Crank-Nicolson method, we calculate ground state wave functions of two-component dipolar Bose-Einstein condensates (BECs) and show that, due to dipole-dipole interaction (DDI), the condensate mixture displays anisotropic phase separation. The effects of DDI, inter-component s-wave scattering, strength of trap potential and particle numbers on the density profiles are investigated. Three types of two-component profiles are present, first cigar, along z-axis and concentric torus, second pancake (or blood cell), in xy-plane, and two non-uniform ellipsoid, separated by the pancake and third two dumbbell shapes.

Pb solubility of the high-temperature superconducting phase Bi2Sr2Ca2Cu3O10+d

International Nuclear Information System (INIS)

Kaesche, S.; Majewski, P.; Aldinger, F.

1994-01-01

For the nominal composition of Bi 2.27x Pb x Sr 2 Ca 2 Cu 3 O 10+d the lead content was varied from x=0.05 to 0.45. The compositions were examined between 830 degrees C and 890 degrees C which is supposed to be the temperature range over which the so-called 2223 phase (Bi 2 Sr 2 Ca 2 Cu 3 O 10+d ) is stable. Only compositions between x=0.18 to 0.36 could be synthesized in a single phase state. For x>0.36 a lead containing phase with a stoichiometry of Pb 4 (Sr,Ca) 5 CuO d is formed, for x 2 Sr 2 CaCu 2 O 8+d and cuprates are the equilibrium phases. The temperature range for the 2223 phase was found to be 830 degrees C to 890 degrees C but the 2223 phase has extremely varying cation ratios over this temperature range. Former single phase 2223 samples turn to multi phase samples when annealed at slightly higher or lower temperatures. A decrease in the Pb solubility with increasing temperature was found for the 2223 phase

Phase separation and nanocrystal formation in Al-based metallic glasses

International Nuclear Information System (INIS)

Antonowicz, Jerzy

2007-01-01

Nanocrystallization in a group of Al-RE and Al-RE-TM (RE = rare earth, TM = transition metal) melt-spun amorphous alloys was studied using in situ small- and wide-angle X-ray scattering techniques (SAXS/WAXS) and transmission electron microscopy (TEM). The SAXS/WAXS measurements were carried out during isothermal annealing at temperatures close to crystallization point. A continuously growing interference maximum shifting progressively toward lower angles was found to develop in SAXS regime. Simultaneously taken WAXS spectra reveal formation of the primary fcc-Al nanocrystalline phase. The presence of the SAXS signal maximum indicates the spatial correlation between the compositional fluctuations. The peak position decay is an evidence of an increase of the fluctuation spacing characteristic for the coarsening stage of phase separation. The SAXS/WAXS data analysis indicates that amorphous phase decomposition triggers and controls the fcc-Al nanocrystalline phase formation. The glassy phase initially decomposes into Al-rich and RE-rich regions with typical lengths scale of about 10 nm. The nanocrystals nucleate preferentially inside the Al-rich amorphous regions and their growth is constrained by the region size because of the sluggish atomic diffusion in the RE-rich zones. A different crystallization mechanism is demonstrated in Al-Y-Ni-Co glass where WAXS spectra show formation of the fcc-Al primary phase but no interference peak in SAXS regime was found

Technical Status Report on the Effect of Phosphate and Aluminum on the Development of Amorphous Phase Separation in Sodium

International Nuclear Information System (INIS)

Cozzi, A.D.

1998-01-01

The objective of the Tank Focus Area ''Optimize Waste Loading'' task is to enhance the definition of the acceptable processing window for high-level waste vitrification plants. One possible manner in which the acceptable processing window may be enhanced is by reducing the uncertainty of various compositional/property models through a specifically defined experimental plan. A reduction in model uncertainty can reduce limitations on current acceptance constraints and may allow for a larger processing or operational window. Enhanced composition/property model predictions coupled with an increased waste loading may decrease the processing time and waste glass disposal costs (i.e., overall lifecycle costs). One of the compositional/property models currently being evaluated by the Tanks Focus Area is related to the development of amorphous phase separation in multi-component borosilicate glasses.Described in this report is the current status for evaluating the effect of phosphorus and alumina on both simple sodium borosilicate and high-level waste glasses on the formation of amorphous phase separation. The goal of this subtask is to increase the understanding of the formation of phase separation by adding significant amounts (3-5 wt. percent) of phosphorus and alumina to well-characterized glasses. Additional scope includes evaluating the effects of thermal history on the formation of amorphous phase separation and durability of select glasses.The development of data, understanding, and quantitative description for composition and kinetic effects on the development of amorphous phase separation will continue in FY99. This effort will provide insight into the compositional and thermal effects on phase stability and will lead to a better understanding of the methods used to predict the development of amorphous phase separation in HLW glasses

A review of phase separation in borosilicate glasses, with reference to nuclear fuel waste immobilization

International Nuclear Information System (INIS)

Taylor, P.

1990-08-01

This report reviews information on miscibility limits in borosilicate glass-forming systems. It includes both a literature survey and an account of experimental work performed within the Canadian Nuclear Fuel Waste Management Program. Emphasis is placed on the measurement and depiction of miscibility limits in multicomponent (mainly quaternary) systems, and the effects of individual components on the occurrence of phase separation. The behaviour of the multicomponent system is related to that of simpler (binary and ternary) glass systems. The possible occurrence of phase separation, as well as its avoidance, during processing of nuclear waste glasses is discussed

Hydrodistillation-adsorption method for the isolation of water-soluble, non-soluble and high volatile compounds from plant materials.

Science.gov (United States)

Mastelić, J; Jerković, I; Blazević, I; Radonić, A; Krstulović, L

2008-08-15

Proposed method of hydrodistillation-adsorption (HDA) on activated carbon and hydrodistillation (HD) with solvent trap were compared for the isolation of water-soluble, non-soluble and high volatile compounds, such as acids, monoterpenes, isothiocyanates and others from carob (Certonia siliqua L.), rosemary (Rosmarinus officinalis L.) and rocket (Eruca sativa L.). Isolated volatiles were analyzed by GC and GC/MS. The main advantages of HDA method over ubiquitous HD method were higher yields of volatile compounds and their simultaneous separation in three fractions that enabled more detail analyses. This method is particularly suitable for the isolation and analysis of the plant volatiles with high amounts of water-soluble compounds. In distinction from previously published adsorption of remaining volatile compounds from distillation water on activated carbon, this method offers simultaneous hydrodistillation and adsorption in the same apparatus.

Separation of phenolic acids from sugarcane rind by online solid-phase extraction with high-speed counter-current chromatography.

Science.gov (United States)

Geng, Ping; Fang, Yingtong; Xie, Ronglong; Hu, Weilun; Xi, Xingjun; Chu, Qiao; Dong, Genlai; Shaheen, Nusrat; Wei, Yun

2017-02-01

Sugarcane rind contains some functional phenolic acids. The separation of these compounds from sugarcane rind is able to realize the integrated utilization of the crop and reduce environment pollution. In this paper, a novel protocol based on interfacing online solid-phase extraction with high-speed counter-current chromatography (HSCCC) was established, aiming at improving and simplifying the process of phenolic acids separation from sugarcane rind. The conditions of online solid-phase extraction with HSCCC involving solvent system, flow rate of mobile phase as well as saturated extent of absorption of solid-phase extraction were optimized to improve extraction efficiency and reduce separation time. The separation of phenolic acids was performed with a two-phase solvent system composed of butanol/acetic acid/water at a volume ratio of 4:1:5, and the developed online solid-phase extraction with HSCCC method was validated and successfully applied for sugarcane rind, and three phenolic acids including 6.73 mg of gallic acid, 10.85 mg of p-coumaric acid, and 2.78 mg of ferulic acid with purities of 60.2, 95.4, and 84%, respectively, were obtained from 150 mg sugarcane rind crude extracts. In addition, the three different elution methods of phenolic acids purification including HSCCC, elution-extrusion counter-current chromatography and back-extrusion counter-current chromatography were compared. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Subsurface migration of petroleum hydrocarbons: A case study of immiscible migration and chromatographic separation

International Nuclear Information System (INIS)

Dawson, H.E.

1991-01-01

The subsurface distribution of a leaked crude oil illustrates the combined influence of both the chemical and physical properties of soil and free product on the migration of petroleum hydrocarbons. Immiscible phase behavior was observed, as well as chromatographic-like separation of the lighter constituents of the crude oil from the heavier constituents. After downward migration through approximately 50 ft of unsaturated, heterogeneous alluvial sediments, the crude oil formed a horizontal plume on top of a perched, saturated zone. Immiscible phase trapping is evident from the occurrence of very high concentration of hydrocarbons in both the vertical and horizontal plumes. Samples taken from the vertical zone of contamination indicate a transition from heavier hydrocarbons near the surface to lighter hydrocarbons at depth. This phenomenon is attributed to chromatographic-like separation of the heavier hydrocarbons by the soil, possibly due to preferential solubility of the lighter hydrocarbons in percolating ran water

Smoothed particle hydrodynamics model for phase separating fluid mixtures. I. General equations

NARCIS (Netherlands)

Thieulot, C; Janssen, LPBM; Espanol, P

We present a thermodynamically consistent discrete fluid particle model for the simulation of a recently proposed set of hydrodynamic equations for a phase separating van der Waals fluid mixture [P. Espanol and C.A.P. Thieulot, J. Chem. Phys. 118, 9109 (2003)]. The discrete model is formulated by

Can visco-elastic phase separation, macromolecular crowding and colloidal physics explain nuclear organisation?

Directory of Open Access Journals (Sweden)

Iborra Francisco J

2007-04-01

Full Text Available Abstract Background The cell nucleus is highly compartmentalized with well-defined domains, it is not well understood how this nuclear order is maintained. Many scientists are fascinated by the different set of structures observed in the nucleus to attribute functions to them. In order to distinguish functional compartments from non-functional aggregates, I believe is important to investigate the biophysical nature of nuclear organisation. Results The various nuclear compartments can be divided broadly as chromatin or protein and/or RNA based, and they have very different dynamic properties. The chromatin compartment displays a slow, constrained diffusional motion. On the other hand, the protein/RNA compartment is very dynamic. Physical systems with dynamical asymmetry go to viscoelastic phase separation. This phase separation phenomenon leads to the formation of a long-lived interaction network of slow components (chromatin scattered within domains rich in fast components (protein/RNA. Moreover, the nucleus is packed with macromolecules in the order of 300 mg/ml. This high concentration of macromolecules produces volume exclusion effects that enhance attractive interactions between macromolecules, known as macromolecular crowding, which favours the formation of compartments. In this paper I hypothesise that nuclear compartmentalization can be explained by viscoelastic phase separation of the dynamically different nuclear components, in combination with macromolecular crowding and the properties of colloidal particles. Conclusion I demonstrate that nuclear structure can satisfy the predictions of this hypothesis. I discuss the functional implications of this phenomenon.

Sequence control of phase separation and dewetting in PS/PVME blend thin films by changing molecular weight of PS.

Science.gov (United States)

Xia, Tian; Qin, Yaping; Huang, Yajiang; Huang, Ting; Xu, Jianhui; Li, Youbing

2016-11-28

The morphology evolution mechanism of polystyrene (PS)/poly (vinyl methyl ether) (PVME) blend thin films with different PS molecular weights (M w ) was studied. It was found that the morphology evolution was closely related to the molecular weight asymmetry between PS and PVME. In the film where M w (PS) ≈ M w (PVME), dewetting happened at the interface between the bottom layer and substrate after SD phase separation. While in the film where M w (PS) > M w (PVME), dewetting happened at the interface between the middle PS/PVME blend layer and bottom PVME layer near the substrate prior to phase separation. The different sequences of phase separation and dewetting and different interface for dewetting occurrence were studied by regarding the competitive effects of viscoelasticity contrast between polymer components and preferential wetting between PVME and the substrate. The viscoelastic nature of the PS component played a crucial role in the sequence of phase separation and dewetting.

Partitioning of semi-soluble organic compounds between the water phase and oil droplets in produced water

Energy Technology Data Exchange (ETDEWEB)

Faksness, Liv-Guri; Grini, Per Gerhard; Daling, Per S

2004-04-01

When selecting produced water treatment technologies, one should focus on reducing the major contributors to the total environmental impact. These are dispersed oil and semi-soluble hydrocarbons, alkylated phenols, and added chemicals. Experiments with produced water have been performed offshore on the Statoil operated platforms Gullfaks C and Statfjord B. These experiments were designed to find how much of the environmentally relevant compounds were dissolved in the water phase and not associated to the dispersed oil in the produced water. Results show that the distribution between the dispersed oil and the water phase varies highly for the different components groups. For example the concentration of PAHs and the C6-C9 alkylated phenols is strongly correlated to the content of dispersed oil. Therefore, the technologies enhancing the removal of dispersed oil have a higher potential for reducing the environmental impact of the produced water than previously considered.

Partitioning of semi-soluble organic compounds between the water phase and oil droplets in produced water

International Nuclear Information System (INIS)

Faksness, Liv-Guri; Grini, Per Gerhard; Daling, Per S.

2004-01-01

When selecting produced water treatment technologies, one should focus on reducing the major contributors to the total environmental impact. These are dispersed oil and semi-soluble hydrocarbons, alkylated phenols, and added chemicals. Experiments with produced water have been performed offshore on the Statoil operated platforms Gullfaks C and Statfjord B. These experiments were designed to find how much of the environmentally relevant compounds were dissolved in the water phase and not associated to the dispersed oil in the produced water. Results show that the distribution between the dispersed oil and the water phase varies highly for the different components groups. For example the concentration of PAHs and the C6-C9 alkylated phenols is strongly correlated to the content of dispersed oil. Therefore, the technologies enhancing the removal of dispersed oil have a higher potential for reducing the environmental impact of the produced water than previously considered

Calculation of solubility of salts in binary aqueous solutions

International Nuclear Information System (INIS)

Kolker, A.R.

1990-01-01

The possibility of theoretical calculation of solubility of some salts of the MX-type, where M - Na, K, Cs; X - F-I, as well as CsNO 3 and others forming no crystal hydrates in the solid phase, and the azeotropic composition in the water-HNO 3 system is studied. The calculational results of solubility are shown to depend very much on the values accepted for the standard free energies of component formation, melting heats and crystallization and on the difference in heat capacity of the melt and the solid phase

[Application of off-line two dimensional reversed-phase liquid chromatography/supercritical fluid chromatography to the separation of the seeds of Trichosanthes kirilowii Maxim].

Science.gov (United States)

Yuan, Yun; Xin, Huaxia; Peng, Ziyue; Fu, Qing; Jin, Yu

2017-07-08

An off-line two dimensional reversed-phase liquid chromatography/supercritical fluid chromatography (2D RPLC/SFC) method was developed for the separation of the seeds of Trichosanthes kirilowii Maxim . ( T. kirilowii .). In the experiment, RPLC was used in the first dimension to analyze the samples. And 12 fractions (F 1 -F 12 ) were obtained according to the chromatographic peak collection mode, the fractions were re-analyzed in both RPLC and SFC modes. The results clearly showed that this 2D method had good orthogonality. The SFC was used as the second dimension. Ethanol- n -hexane (3:7, v/v) was used as a modifier in SFC. The modifier could provide appropriate elution power. When the sample load increased, it could also ensure the solubility of samples. The 2D RPLC/SFC method had obvious advantages for separating the compounds with similar properties, enriching and purifying the trace components. Finally, 150 peaks could be detected. The off-line 2D RPLC/SFC method will be further enlarged to a preparative level for preparation of compounds. The method can provide a practical reference for the purification of chemical constituents and material basis research of the seeds of T. kirilowii . in the future.

Multifunctional nanocomposite hollow fiber membranes by solvent transfer induced phase separation.

Science.gov (United States)

Haase, Martin F; Jeon, Harim; Hough, Noah; Kim, Jong Hak; Stebe, Kathleen J; Lee, Daeyeon

2017-11-01

The decoration of porous membranes with a dense layer of nanoparticles imparts useful functionality and can enhance membrane separation and anti-fouling properties. However, manufacturing of nanoparticle-coated membranes requires multiple steps and tedious processing. Here, we introduce a facile single-step method in which bicontinuous interfacially jammed emulsions are used to form nanoparticle-functionalized hollow fiber membranes. The resulting nanocomposite membranes prepared via solvent transfer-induced phase separation and photopolymerization have exceptionally high nanoparticle loadings (up to 50 wt% silica nanoparticles) and feature densely packed nanoparticles uniformly distributed over the entire membrane surfaces. These structurally well-defined, asymmetric membranes facilitate control over membrane flux and selectivity, enable the formation of stimuli responsive hydrogel nanocomposite membranes, and can be easily modified to introduce antifouling features. This approach forms a foundation for the formation of advanced nanocomposite membranes comprising diverse building blocks with potential applications in water treatment, industrial separations and as catalytic membrane reactors.

Preparation and Characterization of Membranes Formed by Nonsolvent Induced Phase Separation: A Review

KAUST Repository

Guillen, Gregory R.; Pan, Yinjin; Li, Minghua; Hoek, Eric M. V.

2011-01-01

. The body of knowledge has grown exponentially in the past fifty years, which suggests the need for a critical review of the literature. Here we present a review of nonsolvent induced phase separation membrane preparation and characterization for many

Heat and mass transfer in porous media phase separation at temperatures below the lambda-point of He-4

Science.gov (United States)

Yuan, S. W. K.; Frederking, T. H. K.

1986-01-01

Newtonian fluid motion, coupled to heat transfer via latent heat of phase transition, is well known from numerous studies of condensation and boiling. Considerably less knowledge is available for vapor-liquid phase separation in the absence of gravity effect on the transport phenomena. The present studies are focused on heat and mass transfer associated with vapor-liquid phase separation required for long-term storage of the cryogen liquid He II in space vessels. Though space conditions are the dominant mode of interest in advanced equipment, e.g. IR telescopes, the systems may be operated in principle during terrestrial conditions. The latter are considered in the present work. It emphasizes the linear regime including an extrapolation based on variable thermophysical properties. Data taken with a phase separation approach show departures from the linear regime prediction. They agree with a transport equation proposed for the nonlinear, turbulent regime.

Mechanically driven phase separation and corresponding microhardness change in Cu60Zr20Ti20 bulk metallic glass

DEFF Research Database (Denmark)

Cao, Q.P.; Li, J.F.; Zhou, Y.H.

2005-01-01

Rolling deformation of bulk Cu60Zr20Ti20 metallic glass has been performed at cryogenic temperature. The specimens exhibit excellent ductility, and are rolled up to 97% reduction in thickness without fracture. Crystallization is suppressed during the deformation, however, phase separation is obse...... is observed in the glassy matrix when the thickness reduction exceeds 89%. Once the phase separation occurs, the microhardness of the specimen increases drastically, indicating the existence of work hardening by severe plastic deformation of the metallic glass.......Rolling deformation of bulk Cu60Zr20Ti20 metallic glass has been performed at cryogenic temperature. The specimens exhibit excellent ductility, and are rolled up to 97% reduction in thickness without fracture. Crystallization is suppressed during the deformation, however, phase separation...

Determination of radionuclide solubility limits to be used in SR 97. Uncertainties associated to calculated solubilities

Energy Technology Data Exchange (ETDEWEB)

Bruno, J.; Cera, E.; Duro, L.; Jordana, S. [QuantiSci S.L., Barcelona (Spain); Pablo, J. de [DEQ-UPC, Barcelona (Spain); Savage, D. [QuantiSci Ltd., Henley-on-Thames (United Kingdom)

1997-12-01

The thermochemical behaviour of 24 critical radionuclides for the forthcoming SR97 PA exercise is discussed. The available databases are reviewed and updated with new data and an extended database for aqueous and solid species of the radionuclides of interest is proposed. We have calculated solubility limits for the radionuclides of interest under different groundwater compositions. A sensitivity analysis of the calculated solubilities with the composition of the groundwater is presented. Besides selecting the most likely solubility limiting phases, in this work we have used coprecipitation approaches in order to calculate more realistic solubility limits for minor radionuclides, such as Ra, Am and Cm. The comparison between the calculated solubilities and the concentrations measured in relevant natural systems (NA) and in spent fuel leaching experiments helps to assess the validity of the methodology used and to derive source term concentrations for the radionuclides studied. The uncertainties associated to the solubilities of the main radionuclides involved in the spent nuclear fuel have also been discussed in this work. The variability of the groundwater chemistry; redox conditions and temperature of the system have been considered the main factors affecting the solubilities. In this case, a sensitivity analysis has been performed in order to study solubility changes as a function of these parameters. The uncertainties have been calculated by including the values found in a major extent in typical granitic groundwaters. The results obtained from this analysis indicate that there are some radionuclides which are not affected by these parameters, i.e. Ag, Cm, Ho, Nb, Ni, Np, Pu, Se, Sm, Sn, Sr, Tc and U

Separation of the lanthanides on high-efficiency bonded phases and conventional ion-exchange resins

International Nuclear Information System (INIS)

Elchuk, S.; Cassidy, R.M.

1979-01-01

High-performance liquid chromatographic separations (< 20 min) of the lanthanides are illustrated for both 5- and 10-μm bonded-phase strong-acid ion exchangers. The performance of these bonded phase packings is compared with that obtained with a 13-μm styrene-divinylbenzene resin. The eluted metal ions are detected with a variable-wavelength detector after a post-column complexation reaction. The requirements and characteristics of post-column reaction for sensitive metal ion detection after separation on high-performance columns are discussed and the linearity, reproducibility, and sensitivity of the system used in the work are illustrated. The potential of on-column preconcentration for the ultratrace (pg/mL) determination of metal ions is also discussed and illustrated. 7 figures, 2 tables

On the implications of aerosol liquid water and phase separation for organic aerosol mass

Data.gov (United States)

U.S. Environmental Protection Agency — This dataset contains data presented in the figures of the paper "On the implications of aerosol liquid water and phase separation for organic aerosol mass"...

Phase separation and formation of omega phase in the beta matrix of a Ti-V-Cu alloy

Energy Technology Data Exchange (ETDEWEB)

Ng, H.P. [ARC Centre of Excellence for Design in Light Metals, Department of Materials Engineering, Monash University, Victoria 3800 (Australia); Devaraj, A.; Nag, S. [Center for Advanced Research and Technology, Department of Materials Science and Engineering, University of North Texas, Denton, TX (United States); Bettles, C.J. [ARC Centre of Excellence for Design in Light Metals, Department of Materials Engineering, Monash University, Victoria 3800 (Australia); Gibson, M. [CSIRO Process Science and Engineering, Locked Bag 10, Clayton South, Victoria 3169 (Australia); Fraser, H.L. [Center for the Accelerated Maturation of Materials, Department of Materials Science and Engineering, The Ohio State University, Columbus, OH (United States); Muddle, B.C. [ARC Centre of Excellence for Design in Light Metals, Department of Materials Engineering, Monash University, Victoria 3800 (Australia); Banerjee, R., E-mail: rajarshi.banerjee@unt.edu [Center for Advanced Research and Technology, Department of Materials Science and Engineering, University of North Texas, Denton, TX (United States)

2011-05-15

The formation of the {omega} phase in the presence of simultaneous development of compositional modulations (or phase separation) within the body-centered cubic {beta} matrix phase of a Ti-10V-6Cu (wt.%) alloy during continuous cooling has been investigated using a combination of transmission electron microscopy and atom probe tomography. While a water quench from the high-temperature {beta} phase field allows apparently athermal formation of {omega} domains without any significant partitioning of solute or modulation in matrix composition, subsequent annealing at 500 {sup o}C for just 60 s leads to unusually rapid growth of the {omega} domains concurrent with, but apparently independent of, a slower development of finer-scale modulations in solute composition occurring apparently uniformly across both {omega} and {beta} phases. In contrast, on slower air cooling from the solution treatment temperature, there are pronounced compositional fluctuations within the {beta} phase, presumably as a product of spinodal decomposition, that are detectable prior to the formation of {omega} phase. The {omega} phase subsequently forms preferentially in solute-depleted regions of the matrix {beta}, with a composition reflecting the local matrix composition and a solute content significantly lower than the average matrix composition. As a result, it has a cuboidal morphology, distinguishably different from the elliposoidal form that is observed in samples water-quenched and annealed at 500 deg. C.

Evolution of concentration fluctuation during phase separation of polystyrene/poly (vinyl methyl ether) blend in the presence of nanosilica

DEFF Research Database (Denmark)

Chen, Qi; Zuo, Min; Yang, Ruiquan

2017-01-01

and the linearized Cahn–Hilliard theory could describe the amplitude evolution of concentration fluctuation at the early stage of phase separation. Hydrophilic nanosilica A200 dispersed in PVME-rich phase behaved an obvious inhibition effect on the concentration fluctuation of blend matrix, while hydrophobic...... nanosilica R974 dispersed in PS-rich phase had little effect on the concentration fluctuation. The kinetics and amplitude evolution of concentration fluctuation during phase separation for PS/PVME/A200 nanocomposites were remarkably restrained due to the surface adsorption of PVME on A200. As the segmental...

Coarsening and pattern formation during true morphological phase separation in unstable thin films under gravity

Science.gov (United States)

Kumar, Avanish; Narayanam, Chaitanya; Khanna, Rajesh; Puri, Sanjay

2017-12-01

We address in detail the problem of true morphological phase separation (MPS) in three-dimensional or (2 +1 )-dimensional unstable thin liquid films (>100 nm) under the influence of gravity. The free-energy functionals of these films are asymmetric and show two points of common tangency, which facilitates the formation of two equilibrium phases. Three distinct patterns formed by relative preponderance of these phases are clearly identified in "true MPS". Asymmetricity induces two different pathways of pattern formation, viz., defect and direct pathway for true MPS. The pattern formation and phase-ordering dynamics have been studied using statistical measures such as structure factor, correlation function, and growth laws. In the late stage of coarsening, the system reaches into a scaling regime for both pathways, and the characteristic domain size follows the Lifshitz-Slyozov growth law [L (t ) ˜t1 /3] . However, for the defect pathway, there is a crossover of domain growth behavior from L (t ) ˜t1 /4→t1 /3 in the dynamical scaling regime. We also underline the analogies and differences behind the mechanisms of MPS and true MPS in thin liquid films and generic spinodal phase separation in binary mixtures.

Effects of Particles Collision on Separating Gas–Particle Two-Phase Turbulent Flows

KAUST Repository

Sihao, L. V.

2013-10-10

A second-order moment two-phase turbulence model incorporating a particle temperature model based on the kinetic theory of granular flow is applied to investigate the effects of particles collision on separating gas–particle two-phase turbulent flows. In this model, the anisotropy of gas and solid phase two-phase Reynolds stresses and their correlation of velocity fluctuation are fully considered using a presented Reynolds stress model and the transport equation of two-phase stress correlation. Experimental measurements (Xu and Zhou in ASME-FED Summer Meeting, San Francisco, Paper FEDSM99-7909, 1999) are used to validate this model, source codes and prediction results. It showed that the particles collision leads to decrease in the intensity of gas and particle vortices and takes a larger effect on particle turbulent fluctuations. The time-averaged velocity, the fluctuation velocity of gas and particle phase considering particles colli-sion are in good agreement with experimental measurements. Particle kinetic energy is always smaller than gas phase due to energy dissipation from particle collision. Moreover, axial– axial and radial–radial fluctuation velocity correlations have stronger anisotropic behaviors. © King Fahd University of Petroleum and Minerals 2013

Separation of U and Pu be the method of liquid chromatography with free stationary phase in TBP - white spirit - nitric acid system

International Nuclear Information System (INIS)

Litvina, M.N.; Malikov, D.A.; Maryutina, T.A.; Kulyako, Yu.M.; Myasoedov, B.F.

2006-01-01

Possibility is studied of the use of liquid chromatography with free stationary phase for U and Pu separation from organic extract obtained by direct dissolution of MOX-fuel in supercritical CO 2 containing TBP·nHNO 3 complex. As stationary phase solutions of TBP in white-spirit of different concentrations are used. Effect of composition of stationary and mobile phases on separation efficiency is investigated. It is shown that use of liquid chromatography with free stationary phase permits to separate U and Pu in conditions of TBP concentration gradient in stationary phase and HNO 3 concentration gradient in mobile one [ru

Effects of mobile vacancies on the dynamics of ordering and phase separation in nonconserved multicomponent systems

DEFF Research Database (Denmark)

Gilhøj, Henriette; Jeppesen, Claus; Mouritsen, Ole G.

1995-01-01

The effects of mobile vacancies on the dynamics of ordering processes and phase separation in multicomponent systems are studied via Monte Carlo simulations of a two-dimensional seven-state ferromagnetic Potts model with varying degrees of site dilution. The model displays phase equilibria...

Digital holographic microscopy of phase separation in multicomponent lipid membranes

Science.gov (United States)

Farzam Rad, Vahideh; Moradi, Ali-Reza; Darudi, Ahmad; Tayebi, Lobat

2016-12-01

Lateral in-homogeneities in lipid compositions cause microdomains formation and change in the physical properties of biological membranes. With the presence of cholesterol and mixed species of lipids, phospholipid membranes segregate into lateral domains of liquid-ordered and liquid-disordered phases. Coupling of two-dimensional intralayer phase separations and interlayer liquid-crystalline ordering in multicomponent membranes has been previously demonstrated. By the use of digital holographic microscopy (DHMicroscopy), we quantitatively analyzed the volumetric dynamical behavior of such membranes. The specimens are lipid mixtures composed of sphingomyelin, cholesterol, and unsaturated phospholipid, 1,2-dioleoyl-sn-glycero-3-phosphocholine. DHMicroscopy in a transmission mode is an effective tool for quantitative visualization of phase objects. By deriving the associated phase changes, three-dimensional information on the morphology variation of lipid stacks at arbitrary time scales is obtained. Moreover, the thickness distribution of the object at demanded axial planes can be obtained by numerical focusing. Our results show that the volume evolution of lipid domains follows approximately the same universal growth law of previously reported area evolution. However, the thickness of the domains does not alter significantly by time; therefore, the volume evolution is mostly attributed to the changes in area dynamics. These results might be useful in the field of membrane-based functional materials.

Correlation between ionic size and valence state of tetra, penta and hexavalent B-site substitution with solubility limit, phase transformation and multiferroic properties of Bi0.875Eu0.125FeO3

Science.gov (United States)

Mumtaz, Fiza; Jaffari, G. Hassnain; Hassan, Qadeer ul; Shah, S. Ismat

2018-06-01

We present detailed comparative study of effect of isovalent i.e. Eu+3 substitution at A-site and tetra (Ti+4, Zr+4), penta (V+5) and hexavalent (W+6) substitutions at B-site in BiFeO3. Eu+3 substitution led to phase transformation and exhibited mixed phases i.e. rhombohedral and orthorhombic, while tetravalent substituents (Ti+4 and Zr+4) led to stabilization of cubic phase. In higher valent (i.e. V+5 and W+6) cases solubility limit was significantly reduced where orthorhombic phase was observed as in the case of parent compound. Phase transformation as a consequence of increase in microstrain and chemical pressure induced by the substituent has been discussed. Solubility limit of different B-site dopants i.e. Zr, W and V was extracted to 5%, 2% and 2%, respectively. Extra phases in various cases were Bi2Fe4O9, Bi25FeO40, Bi14W2O27, and Bi23V4O44.5 and their fractional amount have been quantified. Ti was substituted up to 15% and has been observed to be completely soluble in the parent compound. Solubility limits depends on ionic radii mismatch and valance difference of Fe+3 and dopant, in which valance difference plays more dominant role. Solubility limit and phase transformation has been explained in terms of change in bond strength and tolerance factor induced by incorporation of dopant which depend on its size and valence state. Detail optical, dielectric, ferroelectric, magnetic and transport properties of Eu and Ti co-doped samples and selected low concentration B-site doped compositions (i.e. 2%) have presented and discussed. Two d-d transitions and three charge transfer transitions were observed within UV-VIS range. Both change in cell volume for the same phase and transformation in crystal structure affects the band gap. Increase in room temperature dielectric constant and saturation polarization was also found to increase in case of Eu-Ti co-doped samples with increasing concentration of Ti. Substitution of Eu at A-site and Ti at B-site led to

Phase Separation and Elastic Properties of Poly(Trimethylene Terephthalate-block-poly(Ethylene Oxide Copolymers

Directory of Open Access Journals (Sweden)

Elżbieta Piesowicz

2016-06-01

Full Text Available A series of poly(trimethylene terephthalate-block-poly(ethylene oxide (PTT-b-PEOT copolymers with different compositions of rigid PTT and flexible PEOT segments were synthesized via condensation in the melt. The influence of the block length and the block ratio on the micro-separated phase structure and elastic properties of the synthesized multiblock copolymers was studied. The PEOT segments in these copolymers were kept constant at 1130, 2130 or 3130 g/mol, whereas the PTT content varied from 30 up to 50 wt %. The phase separation was assessed using differential scanning calorimetry (DSC and dynamic mechanical thermal analysis (DMTA. The crystal structure of the synthesised block copolymers and their microstructure on the manometer scale was evaluated by using WAXS and SAXS analysis. Depending on the PTT/PEOT ratio, but also on the rigid and flexible segment length in PTT-b-PEO copolymers, four different domains were observed i.e.,: a crystalline PTT phase, a crystalline PEO phase (which exists for the whole series based on three types of PEOT segments, an amorphous PTT phase (only at 50 wt % content of PTT rigid segments and an amorphous PEO phase. Moreover, the elastic deformability and reversibility of PTT-b-PEOT block copolymers were studied during a cyclic tensile test. Determined values of permanent set resultant from maximum attained stain (100% and 200% for copolymers were used to evaluate their elastic properties.

Three-phase distillation. Simulation and application to the separation of fermentation products

Energy Technology Data Exchange (ETDEWEB)

Pucci, A; Mikitenko, P; Asselineau, L

1986-01-01

In recent years, most of the simulation methods proposed for solving distillation problems in which three-phase distillation occurs use a Newton-Raphson or a comparable approach which requires an initial estimate of variables close enough to the final answer. A plate-to-plate calculation which is more likely to converge on the solution is presented here. The phase equilibria are represented by the NRTL model. The position of three-phase stages is solved automatically. Another three-phase distillation program operating at infinite reflux first supplies the location of feeds and/or sidestreams and computes the minimum number of stages for a given separation. An application of the proposed method is illustrated by the rectification of butanol-acetone fermentation products. The calculated results are in good agreement with the experimental data obtained from the operation of a laboratory glass-plate-type column. 19 references, 8 figures, 1 table.

Detecting phase separation of freeze-dried binary amorphous systems using pair-wise distribution function and multivariate data analysis

DEFF Research Database (Denmark)

Chieng, Norman; Trnka, Hjalte; Boetker, Johan

2013-01-01

The purpose of this study is to investigate the use of multivariate data analysis for powder X-ray diffraction-pair-wise distribution function (PXRD-PDF) data to detect phase separation in freeze-dried binary amorphous systems. Polymer-polymer and polymer-sugar binary systems at various ratios were...... freeze-dried. All samples were analyzed by PXRD, transformed to PDF and analyzed by principal component analysis (PCA). These results were validated by differential scanning calorimetry (DSC) through characterization of glass transition of the maximally freeze-concentrate solute (Tg'). Analysis of PXRD......-PDF data using PCA provides a more clear 'miscible' or 'phase separated' interpretation through the distribution pattern of samples on a score plot presentation compared to residual plot method. In a phase separated system, samples were found to be evenly distributed around the theoretical PDF profile...

New Liquid Phases for the Gas Chromatographic Separation of Strong Bases on Capillary Columns

OpenAIRE

Grob, K.

2017-01-01

The current practice of pretreating the solid support with free alkali to increase separation efficiency for basic compounds proved to be unsuitable for capillary columns. Instead of this, homogenous organic materials of high base strength are required. We found polyethylene imine (PEI) and polypropylene imine (PPI) to be very efficient as liquid phases of capillary columns for the separation of bases. The preparation of polymers is mentioned. Silanization or acetylation of the free hydroxyl ...

Pseudo-stationary separation materials for highly parallel separations.

Energy Technology Data Exchange (ETDEWEB)

Singh, Anup K.; Palmer, Christopher (University of Montana, Missoula, MT)

2005-05-01

Goal of this study was to develop and characterize novel polymeric materials as pseudostationary phases in electrokinetic chromatography. Fundamental studies have characterized the chromatographic selectivity of the materials as a function of chemical structure and molecular conformation. The selectivities of the polymers has been studied extensively, resulting in a large body of fundamental knowledge regarding the performance and selectivity of polymeric pseudostationary phases. Two polymers have also been used for amino acid and peptide separations, and with laser induced fluorescence detection. The polymers performed well for the separation of derivatized amino acids, and provided some significant differences in selectivity relative to a commonly used micellar pseudostationary phase. The polymers did not perform well for peptide separations. The polymers were compatible with laser induced fluorescence detection, indicating that they should also be compatible with chip-based separations.

Inter and Intra Molecular Phase Separation Environment Effects on PI-PEO Block Copolymers for Batteries and Fuel Cells

Science.gov (United States)

Xue, Chen-Chen; Meador, Mary Ann B.; Eby, R. K.; Cheng, Stephen Z. D.; Ge, Jason J.; Cubon, Valerie A.

2002-01-01

Rod-coil molecules have been introduced as a novel type of block copolymers with unique microstructure due to their ability to self-assemble to various ordered morphologies on a nanometer length scale. These molecules, comprised two homo polymers joined together at one end, microphase separate into ordered, periodic arrays of spheres, cylinders in the bulk state and or solution. To get ordered structure in a reasonable scale, additional force field are applied, such as mechanical shearing, electric field and magnetic field. Recently, progress has made it a possible to develop a new class of polyimides (PI)-Polyethylene oxide (PEO) that are soluble in polar organic solvents. The solvent-soluble PI-PEO has a wide variety of applications in microelectronics, since these PI-PEO films exhibit a high degree of thermal and chemical stability. In this paper, we report the self-assembled ordered structure of PI-PEO molecules formed from concentrate solution.

Two-phase ozonation of chlorinated organics

International Nuclear Information System (INIS)

Bhattacharyya, D.; Freshour, A.; West, D.

1995-01-01

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 NaHCO 3 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 O 3 ), 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 O 3 ) 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 O 3 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

Single-reactor process for producing liquid-phase organic compounds from biomass

Science.gov (United States)

Dumesic, James A [Verona, WI; Simonetti, Dante A [Middleton, WI; Kunkes, Edward L [Madison, WI

2011-12-13

Disclosed is a method for preparing liquid fuel and chemical intermediates from biomass-derived oxygenated hydrocarbons. The method includes the steps of reacting in a single reactor an aqueous solution of a biomass-derived, water-soluble oxygenated hydrocarbon reactant, in the presence of a catalyst comprising a metal selected from the group consisting of Cr, Mn, Fe, Co, Ni, Cu, Mo, Tc, Ru, Rh, Pd, Ag, W, Re, Os, Ir, Pt, and Au, at a temperature, and a pressure, and for a time sufficient to yield a self-separating, three-phase product stream comprising a vapor phase, an organic phase containing linear and/or cyclic mono-oxygenated hydrocarbons, and an aqueous phase.

Argentation gas chromatography revisited: Separation of light olefin/paraffin mixtures using silver-based ionic liquid stationary phases.

Science.gov (United States)

Nan, He; Zhang, Cheng; Venkatesh, Amrit; Rossini, Aaron J; Anderson, Jared L

2017-11-10

Silver ion or argentation chromatography utilizes stationary phases containing silver ions for the separation of unsaturated compounds. In this study, a mixed-ligand silver-based ionic liquid (IL) was evaluated for the first time as a gas chromatographic (GC) stationary phase for the separation of light olefin/paraffin mixtures. The selectivity of the stationary phase toward olefins can be tuned by adjusting the ratio of silver ion and the mixed ligands. The maximum allowable operating temperature of these stationary phases was determined to be between 125°C and 150°C. Nuclear magnetic resonance (NMR) spectroscopy was used to characterize the coordination behavior of the silver-based IL as well as provide an understanding into the retention mechanism of light olefins. Copyright © 2017 Elsevier B.V. All rights reserved.

Investigation of the phase separation of PNIPAM using infrared spectroscopy together with multivariate data analysis

DEFF Research Database (Denmark)

Munk, Tommy; Baldursdottir, Stefania G.; Hietala, S.

2013-01-01

and Gaussian peak fitting was used to investigate the structural changes in aqueous solutions of a polymer, using poly(N-isopropyl acrylamide) (PNIPAM) in the atactic form and with controlled tacticity as a model system. Subtle spectral changes associated with the dehydration and phase separation upon heating...... included peak shifts, an area ratio change of the amide I band to the amide II band and formation of a new peak in the amide I band were efficiently detected. Dehydration and phase separation of PNIPAM occurred in two temperature ranges, one for the atactic and one for isotactic rich part, both involving...... a complex re-organization of the hydrogen bonds and change of the hydration layer. The changes agreed with existing results from other techniques, and new insights were gained into the effect of controlled tacticity on phase transformation behaviour. The study demonstrates that infrared spectroscopy...

Water-induced phase separation of miconazole-poly (vinylpyrrolidone-co-vinyl acetate) amorphous solid dispersions: Insights with confocal fluorescence microscopy.

Science.gov (United States)

Saboo, Sugandha; Taylor, Lynne S

2017-08-30

The aim of this study was to evaluate the utility of confocal fluorescence microscopy (CFM) to study the water-induced phase separation of miconazole-poly (vinylpyrrolidone-co-vinyl acetate) (mico-PVPVA) amorphous solid dispersions (ASDs), induced during preparation, upon storage at high relative humidity (RH) and during dissolution. Different fluorescent dyes were added to drug-polymer films and the location of the dyes was evaluated using CFM. Orthogonal techniques, in particular atomic force microscopy (AFM) coupled with nanoscale infrared spectroscopy (AFM-nanoIR), were used to provide additional analysis of the drug-polymer blends. The initial miscibility of mico-PVPVA ASDs prepared under low humidity conditions was confirmed by AFM-nanoIR. CFM enabled rapid identification of drug-rich and polymer-rich phases in phase separated films prepared under high humidity conditions. The identity of drug- and polymer-rich domains was confirmed using AFM-nanoIR imaging and localized IR spectroscopy, together with Lorentz contact resonance (LCR) measurements. The CFM technique was then utilized successfully to further investigate phase separation in mico-PVPVA films exposed to high RH storage and to visualize phase separation dynamics following film immersion in buffer. CFM is thus a promising new approach to study the phase behavior of ASDs, utilizing drug and polymer specific dyes to visualize the evolution of heterogeneity in films exposed to water. Copyright © 2017 Elsevier B.V. All rights reserved.

Electronic Identification of the Parental Phases and Mesoscopic Phase Separation of K_{x}Fe_{2-y}Se_{2} Superconductors

Directory of Open Access Journals (Sweden)

F. Chen

2011-12-01

Full Text Available The nature of the parent compound of a high-temperature superconductor (HTS often plays a pivotal role in determining its superconductivity. The parent compounds of the cuprate HTSs are antiferromagnetically ordered Mott insulators, while those of the iron-pnictide HTSs are metals with spin-density-wave order. Here we report the electronic identification of two insulating parental phases and one semiconducting parental phase of the newly discovered family of K_{x}Fe_{2-y}Se_{2} superconductors. The two insulating phases exhibit Mott-insulator-like signatures, and one of the insulating phases is even present in the superconducting and semiconducting K_{x}Fe_{2-y}Se_{2} compounds. However, it is mesoscopically phase-separated from the superconducting or semiconducting phase. Moreover, we find that both the superconducting and semiconducting phases are free of the magnetic and vacancy orders present in the insulating phases, and that the electronic structure of the superconducting phase could be developed by doping the semiconducting phase with electrons. The rich electronic properties discovered in these parental phases of the K_{x}Fe_{2-y}Se_{2} superconductors provide the foundation for studying the anomalous behavior in this new class of iron-based superconductors.

Enhanced field emission from PbTiO{sub 3} nanodots prepared by phase separation approach

Energy Technology Data Exchange (ETDEWEB)

Li Jinna; Luo Ming [Department of Materials Science and Engineering, State Key Laboratory of Silicon Materials, Zhejiang University, Hangzhou 310027 (China); Weng Wenjian, E-mail: wengwj@zju.edu.cn [Department of Materials Science and Engineering, State Key Laboratory of Silicon Materials, Zhejiang University, Hangzhou 310027 (China); Cheng Kui; Du Piyi; Shen Ge; Han Gaorong [Department of Materials Science and Engineering, State Key Laboratory of Silicon Materials, Zhejiang University, Hangzhou 310027 (China)

2009-10-15

Uniformly distributed PbTiO{sub 3} nanodots were successfully prepared by phase separation approach. A precursor sol film was first spin-coated on Si wafer and then spontaneously separated into two distinct phases owing to the Marangoni instability. PT nanodots with tailorable size and density were obtained after further heat treatment. X-ray diffraction analysis indicated that these nanodots showed a perovskite structure. An excellent room temperature field emission property of PbTiO{sub 3} nanodots was observed: the minimum turn-on voltage was about 5.3 V/{mu}m; while the emission current density reached about 270 {mu}A cm{sup -2} at an applied field of about 9.25 V/{mu}m.

Boosting Up Performance of Inverted Photovoltaic Cells from Bis(alkylthien-2-yl)dithieno[2,3-d:2',3'-d']benzo[1,2-b:4',5'-b']di thiophene-Based Copolymers by Advantageous Vertical Phase Separation.

Science.gov (United States)

Guo, Pengzhi; Luo, Guoping; Su, Qiang; Li, Jianfeng; Zhang, Peng; Tong, Junfeng; Yang, Chunyan; Xia, Yangjun; Wu, Hongbin

2017-03-29

The photovoltaic cells (PVCs) from conjugated copolymers of PDTBDT-BT and PDTBDT-FBT with 5,10-bis(4,5-didecylthien-2-yl)dithieno[2,3-d:2',3'-d']benzo[1,2-b:4,5-b']dithiophene as electron donor moieties and benzothiadiazole and/or 5,6-difluorobenzothiadiazole as electron acceptor moieties are optimized by employing alcohol-soluble PFN (poly(9,9-bis(3'-(N,N-dimethylamino)propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)) as cathode modification interlayer. The power conversion efficiencies (PCEs) of inverted PVCs (i-PVCs) from PDTBDT-BT and PDTBDT-FBT with devices configuration as ITO/PFN/active layer/MoO 3 /Ag are increased from 4.97% to 8.54% and 5.92% to 8.74%, in contrast to those for the regular PVCs (r-PVCs) with devices configuration as ITO/PEDOT:PSS/active layer/Ca/Al under 100 mW/cm 2 AM 1.5 illumination. The optical modeling calculations and X-ray photoelectron spectroscopy (XPS) investigations reveal that the r-PVCs and i-PVCs from the copolymers exhibit similar light harvesting characteristics, and the enhancements of the PCEs of the i-PVCs from the copolymers are mainly contributed to the favorable vertical phase separation as the strongly polymer-enriched top surface layers and slightly PC 71 BM (phenyl-C 71 -butyric acid methyl ester)-enriched bottom surface layers are correspondingly connected to the anodes and cathodes of the i-PVCs, while they are opposite in the r-PVCs. As we known, it is the first time to experimentally verify that the i-PVCs with alcohol-soluble conjugated polymers cathode modification layers enjoy favorable vertical phase separation.

Chiral stationary phase optimized selectivity liquid chromatography: A strategy for the separation of chiral isomers.

Science.gov (United States)

Hegade, Ravindra Suryakant; De Beer, Maarten; Lynen, Frederic

2017-09-15

Chiral Stationary-Phase Optimized Selectivity Liquid Chromatography (SOSLC) is proposed as a tool to optimally separate mixtures of enantiomers on a set of commercially available coupled chiral columns. This approach allows for the prediction of the separation profiles on any possible combination of the chiral stationary phases based on a limited number of preliminary analyses, followed by automated selection of the optimal column combination. Both the isocratic and gradient SOSLC approach were implemented for prediction of the retention times for a mixture of 4 chiral pairs on all possible combinations of the 5 commercial chiral columns. Predictions in isocratic and gradient mode were performed with a commercially available and with an in-house developed Microsoft visual basic algorithm, respectively. Optimal predictions in the isocratic mode required the coupling of 4 columns whereby relative deviations between the predicted and experimental retention times ranged between 2 and 7%. Gradient predictions led to the coupling of 3 chiral columns allowing baseline separation of all solutes, whereby differences between predictions and experiments ranged between 0 and 12%. The methodology is a novel tool allowing optimizing the separation of mixtures of optical isomers. Copyright © 2017 Elsevier B.V. All rights reserved.

Binary systems solubilities of inorganic and organic compounds

CERN Document Server

Stephen, H

1963-01-01

Solubilities of Inorganic and Organic Compounds, Volume 1: Binary Systems, Part 1 is part of an approximately 5,500-page manual containing a selection from the International Chemical Literature on the Solubilities of Elements, Inorganic Compounds, Metallo-organic and Organic Compounds in Binary, Ternary and Multi-component Systems. A careful survey of the literature in all languages by a panel of scientists specially appointed for the task by the U.S.S.R. Academy of Sciences, Moscow, has made the compilation of this work possible. The complete English edition in five separately bound volumes w

Oxygen sensor equipped engine operation on methanol/gasoline blends and phase separation problems

Energy Technology Data Exchange (ETDEWEB)

Last, A J; Lawson, A; Simmons, E W; Mackay, D; Tsang, M; Maund, G B

1980-01-01

A study was made to address problems related to Canadian utilization of methanol/gasoline blends. These problems are: (1) cold weather operation; (2) water sensitivity to phase separation in winter; (3) vehicle compatibility: fuel/air ratio control, flexibility for vehicle movement outside of areas where methanol might be available. Specifically, the operation of the HydroShear (an in-line hydraulic emulsifier) on the two separated phases of a methanol/gasoline/water blend was examined. Fuel maps, by engine dynamometer testing, were generated using methanol/gasoline blends containing 15% to 65% methanol. The capability of an oxygen sensor, located in the exhaust system, to control the fuel/air ratio was found to be adequate within the 15% to 65% methanol/gasoline blends. A fuel injected Volvo 244DL with lambda-sond emission control and a carburetted Chevrolet Monza with 3-way catalyst closed loop feedback emission control system were the two engines selected for this study.

Flexible Bistable Smectic-A Liquid Crystal Device Using Photolithography and Photoinduced Phase Separation

Directory of Open Access Journals (Sweden)

Yang Lu

2012-01-01

Full Text Available A flexible bistable smectic-A liquid crystal (SmA LC device using pixel-isolated mode was demonstrated, in which SmA LC molecules were isolated in pixels by vertical polymer wall and horizontal polymer layer. The above microstructure was achieved by using ultraviolet (UV photolithography and photoinduced phase separation. The polymer wall was fabricated by photolithography, and then the SmA LC was encapsulated in pixels between polymer wall through UV-induced phase separation, in which the polymer wall acts as supporting structure from mechanical pressure and maintains the cell gap from bending, and the polymer layer acts as adhesive for tight attachment of two substrates. The results demonstrated that all the intrinsic bistable properties of the SmA LC are preserved, and good electrooptical characteristics such as high contrast ratio and excellent stability of the bistable states were characterized. This kind of SmA bistable flexible display has high potential to be used as electronic paper, smart switchable reflective windows, and so forth.

Flow characteristics of centrifugal gas-liquid separator. Investigation with air-water two-phase flow experiment

International Nuclear Information System (INIS)

Yoneda, Kimitoshi; Inada, Fumio

2004-01-01

Air-water two-phase flow experiment was conducted to examine the basic flow characteristics of a centrifugal gas-liquid separator. Vertical transparent test section, which is 4 m in height, was used to imitate the scale of a BWR separator. Flow rate conditions of gas and liquid were fixed at 0.1 m 3 /s and 0.033 m 3 /s, respectively. Radial distributions of two-phase flow characteristics, such as void fraction, gas velocity and bubble chord length, were measured by traversing dual optical void probes in the test section, horizontally. The flow in the standpipe reached to quasi-developed state within the height-to-diameter aspect ratio H/D=10, which in turn can mean the maximum value for an ideal height design of a standpipe. The liquid film in the barrel showed a maximum thickness at 0.5 to 1 m in height from the swirler exit, which was a common result for three different standpipe length conditions, qualitatively and quantitatively. The empirical database obtained in this study would contribute practically to the validation of numerical analyses for an actual separator in a plant, and would also be academically useful for further investigations of two-phase flow in large-diameter pipes. (author)

Densely quaternized poly(arylene ether)s with distinct phase separation for highly anion-conductive membranes

Science.gov (United States)

Hu, Yuanfang; Wang, Bingxi; Li, Xiao; Chen, Dongyang; Zhang, Weiying

2018-05-01

To develop high performance anion exchange membranes (AEMs), a novel bisphenol monomer bearing eight benzylmethyl groups at the outer edge of the molecule was synthesized, which after condensation polymerization with various amounts of 4,4‧-dihydroxydiphenylsulfone and 4,4‧-difluorobenzophenone yielded novel poly(arylene ether)s with densely located benzylmethyl groups. These benzylmethyl groups were then converted to quaternary ammonium groups by radical-initiated bromination and quaternization in tandem, leading to the emergence of densely quaternized poly(arylene ether sulfone)s (QA-PAEs) with controlled ion exchange capacities (IECs) ranging from 1.61 to 2.32 mmol g-1. Both small-angle X-ray scattering (SAXS) and transmission electron microscopy (TEM) studies revealed distinct phase separation in the QA-PAEs. The QA-PAE-40 with an IEC of 2.32 mmol g-1 exhibited a Br- conductivity of 9.2 mS cm-1 and a SO42- conductivity of 14.0 mS cm-1 at room temperature, much higher than those of a control membrane with a similar IEC but without obvious phase separation. Therefore, phase separation of AEMs was validated to be advantageous for the efficient conducting of anions. The experimental results also showed that the QA-PAEs were promising AEM materials, especially for non-alkaline applications.

Separator for alkaline electric batteries and method of making

Science.gov (United States)

Pfluger, H. L. (Inventor); Hoyt, H. E.

1970-01-01

Battery separator membranes of high electrolytic conductivity comprising a cellulose ether and a compatible metallic salt of water soluble aliphatic acids and their hydroxy derivatives are described. It was found that methyl cellulose can be modified by another class of materials, nonpolymeric in nature, to form battery separator membranes of low electrolytic resistance but which have the flexibility of membranes made of unmodified methyl cellulose, and which in many cases enhance flexibility over membranes made with unmodified methyl cellulose. Separator membranes for electrochemical cells comprising a cellulose ether and a modified selected from the group consisting of metallic salts of water soluble alphatic acids and their hydroxy derivatives and to electrochemical cells utilizing said membranes are described.

Paraspeckles: Where Long Noncoding RNA Meets Phase Separation.

Science.gov (United States)

Fox, Archa H; Nakagawa, Shinichi; Hirose, Tetsuro; Bond, Charles S

2018-02-01

Long noncoding RNA (lncRNA) molecules are some of the newest and least understood players in gene regulation. Hence, we need good model systems with well-defined RNA and protein components. One such system is paraspeckles - protein-rich nuclear organelles built around a specific lncRNA scaffold. New discoveries show how paraspeckles are formed through multiple RNA-protein and protein-protein interactions, some of which involve extensive polymerization, and others with multivalent interactions driving phase separation. Once formed, paraspeckles influence gene regulation through sequestration of component proteins and RNAs, with subsequent depletion in other compartments. Here we focus on the dual aspects of paraspeckle structure and function, revealing an emerging role for these dynamic bodies in a multitude of cellular settings. Copyright © 2017 Elsevier Ltd. All rights reserved.

Hygroscopic growth of water soluble organic carbon isolated from atmospheric aerosol collected at US national parks and Storm Peak Laboratory

Science.gov (United States)

Taylor, Nathan F.; Collins, Don R.; Lowenthal, Douglas H.; McCubbin, Ian B.; Gannet Hallar, A.; Samburova, Vera; Zielinska, Barbara; Kumar, Naresh; Mazzoleni, Lynn R.

2017-02-01

Due to the atmospheric abundance and chemical complexity of water soluble organic carbon (WSOC), its contribution to the hydration behavior of atmospheric aerosol is both significant and difficult to assess. For the present study, the hygroscopicity and CCN activity of isolated atmospheric WSOC particulate matter was measured without the compounding effects of common, soluble inorganic aerosol constituents. WSOC was extracted with high purity water from daily high-volume PM2.5 filter samples and separated from water soluble inorganic constituents using solid-phase extraction. The WSOC filter extracts were concentrated and combined to provide sufficient mass for continuous generation of the WSOC-only aerosol over the combined measurement time of the tandem differential mobility analyzer and coupled scanning mobility particle sizer-CCN counter used for the analysis. Aerosol samples were taken at Great Smoky Mountains National Park during the summer of 2006 and fall-winter of 2007-2008; Mount Rainier National Park during the summer of 2009; Storm Peak Laboratory (SPL) near Steamboat Springs, Colorado, during the summer of 2010; and Acadia National Park during the summer of 2011. Across all sampling locations and seasons, the hygroscopic growth of WSOC samples at 90 % RH, expressed in terms of the hygroscopicity parameter, κ, ranged from 0.05 to 0.15. Comparisons between the hygroscopicity of WSOC and that of samples containing all soluble materials extracted from the filters implied a significant modification of the hydration behavior of inorganic components, including decreased hysteresis separating efflorescence and deliquescence and enhanced water uptake between 30 and 70 % RH.

Controlling phase separation in vanadium dioxide thin films via substrate engineering

Science.gov (United States)

Gilbert Corder, Stephanie N.; Jiang, Jianjuan; Chen, Xinzhong; Kittiwatanakul, Salinporn; Tung, I.-Cheng; Zhu, Yi; Zhang, Jiawei; Bechtel, Hans A.; Martin, Michael C.; Carr, G. Lawrence; Lu, Jiwei; Wolf, Stuart A.; Wen, Haidan; Tao, Tiger H.; Liu, Mengkun

2017-10-01

The strong electron-lattice interactions in correlated electron systems provide unique opportunities for altering the material properties with relative ease and flexibility. In this Rapid Communication, we use localized strain control via a focused-ion-beam patterning of Ti O2 substrates to demonstrate that one can selectively engineer the insulator-to-metal transition temperature, the fractional component of the insulating and metallic phases, and the degree of optical anisotropy down to the length scales of the intrinsic phase separation in V O2 thin films without altering the quality of the films. The effects of localized strain control on the strongly correlated electron system are directly visualized by state-of-the-art IR near-field imaging and spectroscopy techniques and x-ray microdiffraction measurements.

A comprehensive review of the lipid cubic phase or in meso method for crystallizing membrane and soluble proteins and complexes

International Nuclear Information System (INIS)

Caffrey, Martin

2015-01-01

A comprehensive and up-to-date review of the lipid cubic phase or in meso method for crystallizing membrane and soluble proteins and complexes is reported. Recent applications of the method for in situ serial crystallography at X-ray free-electron lasers and synchrotrons are described. The lipid cubic phase or in meso method is a robust approach for crystallizing membrane proteins for structure determination. The uptake of the method is such that it is experiencing what can only be described as explosive growth. This timely, comprehensive and up-to-date review introduces the reader to the practice of in meso crystallogenesis, to the associated challenges and to their solutions. A model of how crystallization comes about mechanistically is presented for a more rational approach to crystallization. The possible involvement of the lamellar and inverted hexagonal phases in crystallogenesis and the application of the method to water-soluble, monotopic and lipid-anchored proteins are addressed. How to set up trials manually and automatically with a robot is introduced with reference to open-access online videos that provide a practical guide to all aspects of the method. These range from protein reconstitution to crystal harvesting from the hosting mesophase, which is noted for its viscosity and stickiness. The sponge phase, as an alternative medium in which to perform crystallization, is described. The compatibility of the method with additive lipids, detergents, precipitant-screen components and materials carried along with the protein such as denaturants and reducing agents is considered. The powerful host and additive lipid-screening strategies are described along with how samples that have low protein concentration and cell-free expressed protein can be used. Assaying the protein reconstituted in the bilayer of the cubic phase for function is an important element of quality control and is detailed. Host lipid design for crystallization at low temperatures and for

A comprehensive review of the lipid cubic phase or in meso method for crystallizing membrane and soluble proteins and complexes

Energy Technology Data Exchange (ETDEWEB)

Caffrey, Martin, E-mail: martin.caffrey@tcd.ie [Trinity College Dublin, Dublin (Ireland)

2015-01-01

A comprehensive and up-to-date review of the lipid cubic phase or in meso method for crystallizing membrane and soluble proteins and complexes is reported. Recent applications of the method for in situ serial crystallography at X-ray free-electron lasers and synchrotrons are described. The lipid cubic phase or in meso method is a robust approach for crystallizing membrane proteins for structure determination. The uptake of the method is such that it is experiencing what can only be described as explosive growth. This timely, comprehensive and up-to-date review introduces the reader to the practice of in meso crystallogenesis, to the associated challenges and to their solutions. A model of how crystallization comes about mechanistically is presented for a more rational approach to crystallization. The possible involvement of the lamellar and inverted hexagonal phases in crystallogenesis and the application of the method to water-soluble, monotopic and lipid-anchored proteins are addressed. How to set up trials manually and automatically with a robot is introduced with reference to open-access online videos that provide a practical guide to all aspects of the method. These range from protein reconstitution to crystal harvesting from the hosting mesophase, which is noted for its viscosity and stickiness. The sponge phase, as an alternative medium in which to perform crystallization, is described. The compatibility of the method with additive lipids, detergents, precipitant-screen components and materials carried along with the protein such as denaturants and reducing agents is considered. The powerful host and additive lipid-screening strategies are described along with how samples that have low protein concentration and cell-free expressed protein can be used. Assaying the protein reconstituted in the bilayer of the cubic phase for function is an important element of quality control and is detailed. Host lipid design for crystallization at low temperatures and for

Separation of lanthanum (3) and samarium (3) extraction with tributylphosphate in the solvent presence of solid phase

International Nuclear Information System (INIS)

Korotkevich, I.B.; Kolesnikov, A.A.; Bomshtejn, V.E.

1990-01-01

Lanthanum (3) and samarium (3) extraction from nitric acid solutions by tributylphosphate in the presence of solid phase has been investigated. An increase in samarium α-nitrate distribution factor in the presence of solid phase with a decrease in its concentration in the initial solution and with lanthanum nitrate concentration increase is detected. The greatest effect of separation is observed in samarium nitrate microregion. The method of quantitative extraction of samarium from lanthanum nitrate solutions with samarium-lanthanum separation factor exceeding 50 has been suggested

Citrate-based open-quotes Talspeakclose quotes actinide-lanthanide separation process

International Nuclear Information System (INIS)

Del Cul, G.D.; Toth, L.M.; Bond, W.D.

1997-01-01

Lanthanide elements are produced in relatively high yield by fission of 235 U. Almost all the lanthanide isotopes decay to stable nonradioactive lanthanide isotopes in a relatively short time. Consequently, it is highly advantageous to separate the relatively small actinide fraction from the relatively large quantities of lanthanide isotopes. The TALSPEAK process (Trivalent Actinide Lanthanide Separations by Phosphorus-reagent Extraction from Aqueous Complexes) is one of the few means available to separate the trivalent actinides from the lanthanides. Previous work based on the use of lactic or glycolic acid has shown deleterious effects of some impurity ions such as zirconium(IV), even at concentrations on the order of 10 -4 M. Other perceived problems were the need to maintain the pH and reagent concentrations within a narrow range and a significant solubility of the organic phase at high carboxylic acid concentrations. The authors' cold experiments showed that replacing the traditional extractants glycolic or lactic acid with citric acid eliminates or greatly reduces the deleterious effects produced by impurities such as zirconium. An extensive series of batch tests was done using a wide range of reagent concentrations at different pH values, temperatures, and contact times. The results demonstrated that the citrate-based TALSPEAK can tolerate appreciable changes in pH and reagent concentrations while maintaining an adequate lanthanide extraction. Experiments using a three-stage glass mixer-settler showed a good lanthanide extraction, appropriate phase disengagement, no appreciable deleterious effects due to the presence of impurities such as zirconium, excellent pH buffering, and no significant loss of organic phase

EXOPLANET ALBEDO SPECTRA AND COLORS AS A FUNCTION OF PLANET PHASE, SEPARATION, AND METALLICITY

International Nuclear Information System (INIS)

Cahoy, Kerri L.; Marley, Mark S.; Fortney, Jonathan J.

2010-01-01

First generation space-based optical coronagraphic telescopes will obtain images of cool gas- and ice-giant exoplanets around nearby stars. Exoplanets lying at planet-star separations larger than about 1 AU-where an exoplanet can be resolved from its parent star-have spectra that are dominated by reflected light to beyond 1 μm and punctuated by molecular absorption features. Here, we consider how exoplanet albedo spectra and colors vary as a function of planet-star separation, metallicity, mass, and observed phase for Jupiter and Neptune analogs from 0.35 to 1 μm. We model Jupiter analogs with 1x and 3x the solar abundance of heavy elements, and Neptune analogs with 10x and 30x the solar abundance of heavy elements. Our model planets orbit a solar analog parent star at separations of 0.8 AU, 2 AU, 5 AU, and 10 AU. We use a radiative-convective model to compute temperature-pressure profiles. The giant exoplanets are found to be cloud-free at 0.8 AU, possess H 2 O clouds at 2 AU, and have both NH 3 and H 2 O clouds at 5 AU and 10 AU. For each model planet we compute moderate resolution (R = λ/Δλ ∼ 800) albedo spectra as a function of phase. We also consider low-resolution spectra and colors that are more consistent with the capabilities of early direct imaging capabilities. As expected, the presence and vertical structure of clouds strongly influence the albedo spectra since cloud particles not only affect optical depth but also have highly directional scattering properties. Observations at different phases also probe different volumes of atmosphere as the source-observer geometry changes. Because the images of the planets themselves will be unresolved, their phase will not necessarily be immediately obvious, and multiple observations will be needed to discriminate between the effects of planet-star separation, metallicity, and phase on the observed albedo spectra. We consider the range of these combined effects on spectra and colors. For example, we find that

Finsler Geometry Modeling of Phase Separation in Multi-Component Membranes

Directory of Open Access Journals (Sweden)

Satoshi Usui

2016-08-01

Full Text Available A Finsler geometric surface model is studied as a coarse-grained model for membranes of three components, such as zwitterionic phospholipid (DOPC, lipid (DPPC and an organic molecule (cholesterol. To understand the phase separation of liquid-ordered (DPPC rich L o and liquid-disordered (DOPC rich L d , we introduce a binary variable σ ( = ± 1 into the triangulated surface model. We numerically determine that two circular and stripe domains appear on the surface. The dependence of the morphological change on the area fraction of L o is consistent with existing experimental results. This provides us with a clear understanding of the origin of the line tension energy, which has been used to understand these morphological changes in three-component membranes. In addition to these two circular and stripe domains, a raft-like domain and budding domain are also observed, and the several corresponding phase diagrams are obtained.

Soluble Molecularly Imprinted Nanorods for Homogeneous Molecular Recognition

Directory of Open Access Journals (Sweden)

Rongning Liang

2018-03-01

Full Text Available Nowadays, it is still difficult for molecularly imprinted polymers (MIPs to achieve homogeneous recognition since they cannot be easily dissolved in organic or aqueous phase. To address this issue, soluble molecularly imprinted nanorods have been synthesized by using soluble polyaniline doped with a functionalized organic protonic acid as the polymer matrix. By employing 1-naphthoic acid as a model, the proposed imprinted nanorods exhibit an excellent solubility and good homogeneous recognition ability. The imprinting factor for the soluble imprinted nanoroads is 6.8. The equilibrium dissociation constant and the apparent maximum number of the proposed imprinted nanorods are 248.5 μM and 22.1 μmol/g, respectively. We believe that such imprinted nanorods may provide an appealing substitute for natural receptors in homogeneous recognition related fields.

Soluble Molecularly Imprinted Nanorods for Homogeneous Molecular Recognition

Science.gov (United States)

Liang, Rongning; Wang, Tiantian; Zhang, Huan; Yao, Ruiqing; Qin, Wei

2018-03-01

Nowadays, it is still difficult for molecularly imprinted polymer (MIPs) to achieve homogeneous recognition since they cannot be easily dissolved in organic or aqueous phase. To address this issue, soluble molecularly imprinted nanorods have been synthesized by using soluble polyaniline doped with a functionalized organic protonic acid as the polymer matrix. By employing 1-naphthoic acid as a model, the proposed imprinted nanorods exhibit an excellent solubility and good homogeneous recognition ability. The imprinting factor for the soluble imprinted nanoroads is 6.8. The equilibrium dissociation constant and the apparent maximum number of the proposed imprinted nanorods are 248.5 μM and 22.1 μmol/g, respectively. We believe that such imprinted nanorods may provide an appealing substitute for natural receptors in homogeneous recognition related fields.

Preparation of a novel dual-function strong cation exchange/hydrophobic interaction chromatography stationary phase for protein separation.

Science.gov (United States)

Zhao, Kailou; Yang, Li; Wang, Xuejiao; Bai, Quan; Yang, Fan; Wang, Fei

2012-08-30

We have explored a novel dual-function stationary phase which combines both strong cation exchange (SCX) and hydrophobic interaction chromatography (HIC) characteristics. The novel dual-function stationary phase is based on porous and spherical silica gel functionalized with ligand containing sulfonic and benzyl groups capable of electrostatic and hydrophobic interaction functionalities, which displays HIC character in a high salt concentration, and IEC character in a low salt concentration in mobile phase employed. As a result, it can be employed to separate proteins with SCX and HIC modes, respectively. The resolution and selectivity of the dual-function stationary phase were evaluated under both HIC and SCX modes with standard proteins and can be comparable to that of conventional IEC and HIC columns. More than 96% of mass and bioactivity recoveries of proteins can be achieved in both HIC and SCX modes, respectively. The results indicated that the novel dual-function column could replace two individual SCX and HIC columns for protein separation. Mixed retention mechanism of proteins on this dual-function column based on stoichiometric displacement theory (SDT) in LC was investigated to find the optimal balance of the magnitude of electrostatic and hydrophobic interactions between protein and the ligand on the silica surface in order to obtain high resolution and selectivity for protein separation. In addition, the effects of the hydrophobicity of the ligand of the dual-function packings and pH of the mobile phase used on protein separation were also investigated in detail. The results show that the ligand with suitable hydrophobicity to match the electrostatic interaction is very important to prepare the dual-function stationary phase, and a better resolution and selectivity can be obtained at pH 6.5 in SCX mode. Therefore, the dual-function column can replace two individual SCX and HIC columns for protein separation and be used to set up two-dimensional liquid

Phase separation over an extended compositional range: Studies of the Ca1-xBixMnO3 (x≤0.25) phase diagram

International Nuclear Information System (INIS)

Santhosh, P. N.; Goldberger, J.; Woodward, P. M.; Vogt, T.; Lee, W. P.; Epstein, A. J.

2000-01-01

Phase transitions on the electron-doped side of the Ca 1-x Bi x MnO 3 system (x≤0.25) have been investigated using high-resolution synchrotron x-ray and neutron powder-diffraction techniques, electrical transport and magnetic susceptibility measurements. At room temperature all samples investigated were single phase, paramagnetic conductors (ρ 3 (space group Pnma). The Mn-O-Mn angles remain nearly constant from x=0 to x=0.25, while the Mn-O distances steadily increase with the Mn 3+ content. Three distinct phases are observed at 25 K. The first one, observed from 0.15≥x≥0.03, is characterized by the absence of charge and orbital ordering, a canted G-type antiferromagnetic spin structure, and delocalized electron transport. The second phase, observed from 0.25≥x≥0.12 (single phase at x=0.18), is characterized by pronounced orbital ordering, a C-type antiferromagnetic spin structure, and insulating behavior. The third low-temperature phase, observed for x≥0.20, is characterized by orbital and magnetic ordering similar to the Wigner crystal structure previously observed for Ca 0.67 La 0.33 MnO 3 , but with a 4axbx2c unit cell. The most striking feature of the phase diagram is the wide compositional range over which low-temperature phase separation is observed. Only those samples with x<0.12 and x=0.18 did not undergo phase separation upon cooling. We show that this behavior cannot be attributed to compositional variations, and therefore, propose that anisotropic strain interactions between crystallites may be partially responsible for this behavior

(Ce,Gd)O_2−δ-based dual phase membranes for oxygen separation

DEFF Research Database (Denmark)

Samson, Alfred Junio; Søgaard, Martin; Hendriksen, Peter Vang

2014-01-01

and characterized with respect to sinterability, oxygen permeation rate, phase interaction, and microstructure. These factors are important when considering the development of composite membranes with CGO as the oxide ion conducting phase. Composite membranes with relative densities >91% were fabricated using....... The results indicate a promising prospect for further tailoring and optimization of CGO-based composites for application in oxygen separation....

Dual Activity of Hydroxypropyl-β-Cyclodextrin and Water-Soluble Carriers on the Solubility of Carvedilol.

Science.gov (United States)

Zoghbi, Abdelmoumin; Geng, Tianjiao; Wang, Bo

2017-11-01

Carvedilol (CAR) is a non-selective α and β blocker categorized as class II drug with low water solubility. Several recent studies have investigated ways to overcome this problem. The aim of the present study was to combine two of these methods: the inclusion complex using hydroxypropyl-β-cyclodextrin (HPβCD) with solid dispersion using two carriers: Poloxamer 188 (PLX) and Polyvinylpyrrolidone K-30 (PVP) to enhance the solubility, bioavailability, and the stability of CAR. Kneading method was used to prepare CAR-HPβCD inclusion complex (KD). The action of different carriers separately and in combination on Carvedilol solubility was investigated in three series. CAR-carrier and KD-carrier solid dispersions were prepared by solvent evaporation method. In vitro dissolution test was conducted in three different media: double-distilled water (DDW), simulative gastric fluid (SGF), and PBS pH 6.8 (PBS). The interactions between CAR, HPβCD, and different carriers were explored by Fourier transform infrared spectroscopy (FTIR), powder X-ray diffractometry (XRD), and differential scanning colorimetry (DSC). The results showed higher solubility of CAR in KD-PVP solid dispersions up to 70, 25, and 22 fold compared to pure CAR in DDW, SGF, and PBS, respectively. DSC and XRD analyses indicated an improved degree of transformation of CAR in KD-PVP solid dispersion from crystalline to amorphous state. This study provides a new successful combination of two polymers with the dual action of HPβCD and PLX/PVP on water solubility and bioavailability of CAR.

Solubility of Tc(IV) oxides

International Nuclear Information System (INIS)

Liu, D.J.; Fan, X.H.

2005-01-01

Full text of publication follows: The deep geological disposal of the high level radioactive wastes is expected to be a safer disposal method in most countries. The long-lived fission product 99 Tc is present in large quantities in nuclear wastes and its chemical behavior in aqueous solution is of considerable interest. Under the reducing conditions, expected to exist in a deep geological repository, it is generally predicted that technetium will be present as TcO 2 .nH 2 O. The solubility of Tc(IV) is used as a source term in performance assessment of radioactive waste repository. Technetium oxide was prepared by reduction of a technetate solution with Sn 2+ . The solubility of Tc(IV) oxide has been determined in simulated groundwater and re-distilled water under aerobic and anaerobic conditions. The effects of pH and CO 3 2- concentration of solution on solubility of Tc(IV) oxide were studied. The concentration of total technetium and Tc(IV) species in the solutions were periodically determined by separating the oxidized and reduced technetium species using a solvent extraction procedure and counting the beta activity of the 99 Tc with a liquid scintillation counter. The experimental results show that the rate of oxidation of Tc(IV) in simulated groundwater and re-distilled water is about (1.49∼1.86) x 10 -9 mol/(L.d) under aerobic conditions, but Tc(IV) in simulated groundwater and re-distilled water is not oxidized under anaerobic conditions. Under aerobic or anaerobic conditions the solubility of Tc(IV) oxide in simulated groundwater and re-distilled water is equal on the whole after centrifugation or ultrafiltration. The solubility of Tc(IV) oxide decreases with the increase of pH at pH 10 and is pH independent in the range 2 -8 to 10 -9 mol/L at 2 3 2- concentration. These data could be used to estimate the Tc(IV) solubility for cases where solubility limits transport of technetium in reducing environments of high-level waste repositories. (authors)

Extended solid solubility of a Co–Cr system by mechanical alloying

International Nuclear Information System (INIS)

Betancourt-Cantera, J.A.; Sánchez-De Jesús, F.; Torres-Villaseñor, G.; Bolarín-Miró, A.M.; Cortés-Escobedo, C.A.

2012-01-01

Highlights: ► Solubility of the Co–Cr system is modified by means of Mechanical Alloying (MA). ► MA induces the formation of new solid solutions of Co–Cr system in non-equilibrium. ► MA promote the formation of metastable Co–Cr phases with greater solubility. - Abstract: Mechanical alloying, MA, has been successfully used to extend the limits of solid solubility in many commercially important metallic systems. The aim of this work is to demonstrate that MA modifies the solid solubility of the Co–Cr system. Co and Cr elemental powders were used as precursors and mixed in an adequate weight ratio to obtain Co 100−x Cr x (0 ≤ x ≤ 100, Δx = 10) to study the effect of mechanical processing in the solubility of the Co–Cr system. Processing was carried out at room temperature in a shaker mixer mill using vials and balls of hardened steel as milling media with a ball:powder weight ratio of 10:1. Crystalline structure characterization of the milled powders was conducted using X-ray diffraction, and phase transformations as a function of composition were analyzed. Thermal analysis confirmed structural changes occurred in the mechanically alloyed powders. The evolution of the phase transformations with composition is reported for each composition. The results showed that after high energy ball milling for 7 h, the solid solubility between Co and Cr could be evidently extended, despite the low solid solubility at the equilibrium conditions of this system. Additionally, the micrographs of the milled powders showed that increasing composition of chromium changes the shape and size of the particles while simultaneously reducing their agglomeration; this effect is possibly attributed to the brittleness of elemental chrome.

Extended solid solubility of a Co-Cr system by mechanical alloying

Energy Technology Data Exchange (ETDEWEB)

Betancourt-Cantera, J.A. [Area Academica de Ciencias de la Tierra y Materiales, UAEH Carr. Pachuca-Tulancingo Km. 4.5, Pachuca, Hidalgo 42184 (Mexico); Sanchez-De Jesus, F., E-mail: fsanchez@uaeh.edu.mx [Area Academica de Ciencias de la Tierra y Materiales, UAEH Carr. Pachuca-Tulancingo Km. 4.5, Pachuca, Hidalgo 42184 (Mexico); Torres-Villasenor, G. [Instituto de Investigaciones en Materiales-UNAM, Apdo. Postal 70-360, 04510 Mexico, DF (Mexico); Bolarin-Miro, A.M. [Area Academica de Ciencias de la Tierra y Materiales, UAEH Carr. Pachuca-Tulancingo Km. 4.5, Pachuca, Hidalgo 42184 (Mexico); Cortes-Escobedo, C.A. [Centro de Investigacion e Innovacion Tecnologica del IPN Cda. CECATI S/N, Col. Sta. Catarina, Azcapotzalco, 02250 Mexico, DF (Mexico)

2012-07-15

Highlights: Black-Right-Pointing-Pointer Solubility of the Co-Cr system is modified by means of Mechanical Alloying (MA). Black-Right-Pointing-Pointer MA induces the formation of new solid solutions of Co-Cr system in non-equilibrium. Black-Right-Pointing-Pointer MA promote the formation of metastable Co-Cr phases with greater solubility. - Abstract: Mechanical alloying, MA, has been successfully used to extend the limits of solid solubility in many commercially important metallic systems. The aim of this work is to demonstrate that MA modifies the solid solubility of the Co-Cr system. Co and Cr elemental powders were used as precursors and mixed in an adequate weight ratio to obtain Co{sub 100-x}Cr{sub x} (0 {<=} x {<=} 100, {Delta}x = 10) to study the effect of mechanical processing in the solubility of the Co-Cr system. Processing was carried out at room temperature in a shaker mixer mill using vials and balls of hardened steel as milling media with a ball:powder weight ratio of 10:1. Crystalline structure characterization of the milled powders was conducted using X-ray diffraction, and phase transformations as a function of composition were analyzed. Thermal analysis confirmed structural changes occurred in the mechanically alloyed powders. The evolution of the phase transformations with composition is reported for each composition. The results showed that after high energy ball milling for 7 h, the solid solubility between Co and Cr could be evidently extended, despite the low solid solubility at the equilibrium conditions of this system. Additionally, the micrographs of the milled powders showed that increasing composition of chromium changes the shape and size of the particles while simultaneously reducing their agglomeration; this effect is possibly attributed to the brittleness of elemental chrome.

Charge pattern matching as a ‘fuzzy’ mode of molecular recognition for the functional phase separations of intrinsically disordered proteins

Science.gov (United States)

Lin, Yi-Hsuan; Brady, Jacob P.; Forman-Kay, Julie D.; Chan, Hue Sun

2017-11-01

Biologically functional liquid-liquid phase separation of intrinsically disordered proteins (IDPs) is driven by interactions encoded by their amino acid sequences. Little is currently known about the molecular recognition mechanisms for distributing different IDP sequences into various cellular membraneless compartments. Pertinent physics was addressed recently by applying random-phase-approximation (RPA) polymer theory to electrostatics, which is a major energetic component governing IDP phase properties. RPA accounts for charge patterns and thus has advantages over Flory-Huggins (FH) and Overbeek-Voorn mean-field theories. To make progress toward deciphering the phase behaviors of multiple IDP sequences, the RPA formulation for one IDP species plus solvent is hereby extended to treat polyampholyte solutions containing two IDP species plus solvent. The new formulation generally allows for binary coexistence of two phases, each containing a different set of volume fractions ({φ }1,{φ }2) for the two different IDP sequences. The asymmetry between the two predicted coexisting phases with regard to their {φ }1/{φ }2 ratios for the two sequences increases with increasing mismatch between their charge patterns. This finding points to a multivalent, stochastic, ‘fuzzy’ mode of molecular recognition that helps populate various IDP sequences differentially into separate phase compartments. An intuitive illustration of this trend is provided by FH models, whereby a hypothetical case of ternary coexistence is also explored. Augmentations of the present RPA theory with a relative permittivity {ɛ }{{r}}(φ ) that depends on IDP volume fraction φ ={φ }1+{φ }2 lead to higher propensities to phase separate, in line with the case with one IDP species we studied previously. Notably, the cooperative, phase-separation-enhancing effects predicted by the prescriptions for {ɛ }{{r}}(φ ) we deem physically plausible are much more prominent than that entailed by common

Separation of lanthanum (3) and neodymium (3) by tributyl phosphate extraction in the presence of solid phase

International Nuclear Information System (INIS)

Korotkevich, I.B.; Kolesnikov, A.A.; Bomshtejn, V.E.; Shikhaleeva, N.N.

1987-01-01

Lanthanum (3) and neodymium (3) extraction from nitric acid solutions by tributyl phosphate in the presence of solid phase of the element nitrates is investigated. An increase in distribution of neodymium nitrate in the presence of solid phase with the decrease in its concentration in the initial solution and with the increase in lanthanum nitrate concentration is detected. The highest effect of extractive-crystallizational separation is observed in the range of neodymium nitrate microconcentrations. A method of neodymium quantitative extraction from lanthanum nitrate solutions with neodymium - lanthanum separation coefficient exceeding 25 is suggested

Water-soluble phosphine-protected Au9 clusters: Electronic structures and nuclearity conversion via phase transfer

Science.gov (United States)

Yao, Hiroshi; Tsubota, Shuhei

2017-08-01

In this article, isolation, exploration of electronic structures, and nuclearity conversion of water-soluble triphenylphosphine monosulfonate (TPPS)-protected nonagold (Au9) clusters are outlined. The Au9 clusters are obtained by the reduction of solutions containing TPPS and HAuCl4 and subsequent electrophoretic fractionation. Mass spectrometry and elemental analysis reveal the formation of [Au9(TPPS)8]5- nonagold cluster. UV-vis absorption and magnetic circular dichroism (MCD) spectra of aqueous [Au9(TPPS)8]5- are quite similar to those of [Au9(PPh3)8]3+ in organic solvent, so the solution-phase structures are likely similar for both systems. Simultaneous deconvolution analysis of absorption and MCD spectra demonstrates the presence of some weak electronic transitions that are essentially unresolved in the UV-vis absorption. Quantum chemical calculations for a model compound [Au9(pH3)8]3+ show that the possible (solution-phase) skeletal structure of the nonagold cluster has D2h core symmetry rather than C4-symmetrical centered crown conformation, which is known as the crystal form of the Au9 compound. Moreover, we find a new nuclearity conversion route from Au9 to Au8; that is, phase transfer of aqueous [Au9(TPPS)8]5- into chloroform using tetraoctylammonium bromide yields [Au8(TPPS)8]6- clusters in the absence of excess phosphine.

Phase transitions, solubility, and crystallization kinetics of phytosterols and phytosterol-oil blends.

Science.gov (United States)

Vaikousi, Hariklia; Lazaridou, Athina; Biliaderis, Costas G; Zawistowski, Jerzy

2007-03-07

The thermal properties, solubility characteristics, and crystallization kinetics of four commercial phytosterol preparations (soy and wood sterols and stanols) and their blends with corn oil were examined. Differential scanning calorimetry (DSC) revealed narrow melting peaks between 138 and 145 degrees C for all phytosterol samples, reversible on rescan. Broader and less symmetrical melting transitions at lower temperatures with increasing oil content were observed for two samples of phytosterol-oil admixtures. The estimated, from the solubility law, deltaH values (34.7 and 70.7 mJ/mg for wood sterols and stanols, respectively), were similar to the DSC experimental data. Fatty acid esters of soy stanols differing in the chain length of the acyl groups (C2-C12) exhibited suppression of the melting point and increase of the fusion enthalpy with increasing chain length of the acyl group; the propionate ester exhibited the highest melting point (Tm: 151 degrees C) among all stanol-fatty acid esters. Solubility of phytosterols in corn oil was low (2-3% w/w at 25 degrees C) and increased slightly with a temperature rise. Plant sterols appeared more soluble than stanols with higher critical concentrations at saturation. The induction time for recrystallization of sterol-oil liquid blends, as determined by spectrophotometry, depended on the supersaturation ratio. The calculated interfacial free energies between crystalline sediments and oil were smaller for sterol samples (3.80 and 3.85 mJ/m2) than stanol mixtures (5.95 and 6.07 mJ/m2), in accord with the higher solubility of the sterol crystals in corn oil. The XRD patterns and light microscopy revealed some differences in the characteristics among the native and recrystallized in oil phytosterol preparations.