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Search Results: 1 - 10 of 15199 matches for " liquid phase separation "
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Preparation of Microcapsules with Liquid Droplet Coalescence Method Followed by Phase Separation  [PDF]
Yasushi Yokoyama, Kiyomi Fuchigami, Yoshinari Taguchi, Masato Tanaka
Journal of Encapsulation and Adsorption Sciences (JEAS) , 2013, DOI: 10.4236/jeas.2013.33011
Abstract:

Novel preparation method of microencapsules was developed on the basis of the liquid coalescence method followed by phase separation. Oil droplets of limonene dissolving expanded polystyrene as a shell material were forced to collide and coalesce with the Isopar oil droplets of core material in the continuous wates phase. When two kinds of oil droplets are collided and coalesced with each other, expanded polystyrene dissolved in the limonene oil may be phase-separated in the oil droplets newly formed to form the microcapsule shell, because the Isopar oil was a poor solvent for expanded polystyrene but a good solvent for the limonene oil. In the experiment, the diameter (or number) of limonene oil droplets dissolving expanded polystyrene was mainly changed, because the coalescence frequency between the droplets is strongly dependent on the number of droplets. Favorable core shell types of microcapsules with the shell thickness from 1.0 to 5.0 μm were able to be prepared under all the experimental conditions adopted here.

Preparation of Composite Particles Made of Biodegradable Polymer and a Few Additives with Phase Separation Followed by Drying-in-Liquid  [PDF]
Mitsuru Kutsuwada, Yoshinari Taguchi, Masato Tanaka
Journal of Encapsulation and Adsorption Sciences (JEAS) , 2015, DOI: 10.4236/jeas.2015.51002
Abstract: It was tried to prepare the biodegradable composite particles by the phase separation method followed by the drying-in-liquid method. The composite particles were made of poly-ε-caprolac-tone, quaternary ammonium, carbon black and wax. In the experiment, acetone and water were selected as a good solvent and a poor solvent for poly-ε-caprolactone, quaternary ammonium and wax, respectively. The composite particles were prepared by changing the surfactant species and their concentration, the feeding velocity of water and the weight ratio of poly-ε-caprolactone with larger molecular weight to one with smaller molecular weight. The composite particles with the inner structure in which carbon black, quaternary ammonium and wax were coated well with poly-ε-caprolactone could be prepared by the preparation method presented in this study. The structure and the mean diameter of composite particles were strongly affected by the feeding velocity of water. The higher the feeding velocity of water, the larger the mean diameter of composite particles. The mean diameter was drastically decreased with the surfactant concentration and increased with the added amount of poly-ε-caprolactant with larger molecular weight.
Hollow Fiber Supported Liquid Membrane for Separation and Recovery of 152+154Eu and 90Sr from Aqueous Acidic Wastes  [PDF]
A. T. Kassem, Y. T. Selim, N. El-Said
American Journal of Analytical Chemistry (AJAC) , 2015, DOI: 10.4236/ajac.2015.67061
Abstract: Separation and recovery of 152+154Eu and 90Sr from radioactive waste using tracer concentration from active material from waste tank in the ET-RR1 Egypt via hollow fiber supported liquid membrane (HFSLM) were achieved. The Polypropylene was used as supporter to carrier 0.5M Cyanex301/kerosene (bis(2,4,4-trimethylpentyl)dithiophosphinic acid and 0.1MEDTA as stripping of 152+154Eu and 90Sr ions from nitrate medium at pH ~3.6. The separation factor was found to be ~4 for 152+154Eu over 90Sr. The aqueous feed of mass transfer coefficient (ki) and the organic mass transfer coefficient (km) were calculated to be (1.52 and 4.5) × 102cm/s, respectively. In addition, the mass transfer modeling was performed and the validity of the developed model from experimental data was found to join in well with the theoretical values when the Cyanex301 concentration is higher than 1% (v/v). The number of cycles evaluated for complete separation of 152+154Eu and 90Sr is five cycles.
Cromatografia líquida com fase quiral aplicada na separa??o enantiomérica de fármacos cardiovasculares
Singh, Anil Kumar;Kedor-Hackmann, érika Rosa Maria;Santoro, Maria Inês Rocha Miritello;
Revista Brasileira de Ciências Farmacêuticas , 2006, DOI: 10.1590/S1516-93322006000400011
Abstract: the majority of frequently prescribed therapeutic agents are formulated and commercialized in the racemic form, even though, for some of them, it has already been demonstrated that the pharmacological and/or toxicological effects are associated only with one of the enantiomers. moreover, it is well known that these antipodes can present different pharmacokinetic and pharmacodynamic profiles. in this work we selected drugs that belong to an important group of pharmaceuticals, frequently prescribed in the treatment of cardiovascular disorders. the direct enantiomeric separations of atenolol, betaxolol, metoprolol and nadolol were obtained using the chiral stationary phase cellulose tris-3,5-dimethylphenyl-carbamate, chiralcel od? (250 x 4,6 mm, 10 μm). the enantiomers of pindolol were separated with the chiral stationary phase derived from dinitro-benzoyl (dnb) (s, s) a-burke 2? (250x4.6 mm, 10 μm). the drugs were chromatographed at room temperature, with injection volumes of 20 μl. the detention was made at 276 nm except for pindolol, which was detected at 220 nm. the proposed methods in this work using hplc-csp offer advantages over contemporaneous techniques of enantiomeric separation, being rapid and efficient, and can be used in the simultaneous quantitative analysis of referred enantiomers in pharmaceutical preparations and biological samples.
The liquid phase separation of Bi-Ga hypermonotectic alloy under acoustic levitation condition
ZhenYu Hong,YongJun Lü,WenJun Xie,BingBo Wei
Chinese Science Bulletin , 2007, DOI: 10.1007/s11434-007-0231-z
Abstract: Containerless treatment of Bi-58.5at%Ga hypermonotectic alloy is successfully performed with acoustic levitation technique. Under acoustic levitation condition, the second phase (Ga) distributes almost homogeneously in solidification sample, opposite to macrosegregation in solidification sample under conventional condition. Stokes motion of the second liquid droplet (Ga) is significantly restrained under acoustic levitation condition. The analyses indicate that the melt vibration in the gravity direction forced by acoustic field can induce steady flow around the second liquid droplet, which influences droplet shape during its moving upward and consequently restrains Stokes motion velocity of the second liquid droplet.
Development of a Rapid and Efficient Liquid Chromatography Method for Determination of Gibberellin A4 in Plant Tissue, with Solid Phase Extraction for Purification and Quantification  [PDF]
Julia Medrano Macías, Rahim Foroughbakhch Pournavab, Manuel Humberto Reyes-Valdés, Adalberto Benavides-Mendoza
American Journal of Plant Sciences (AJPS) , 2014, DOI: 10.4236/ajps.2014.55072
Abstract:

A new, rapid and efficient reverse phase Liquid Chromatography (RP-LC) method was developed for determination of Gibberellin A4 (GA4) in samples of flower stalk of Dasylirion cedrosanum and vegetative tissue of Epithelantha micromeris. Purification of GA4 was carried out by solid phase extraction (SPE), in Epithelantha micromeris. In the chromatography method was obtaining a retention time of 2.1 min, using Hypersil GOLD C-18 column (100 × 4.6 mm dim and size particle 5 μ), mobile phase 50/50 acetonitrile/water and a flow 1.0 ml/min. Detection was carried out by a UV detector set at 205 nm, and a quantization limit of 0.4 mg/L. The obtained correlation coefficient was 0.995.

Understanding atomic-scale phase separation of liquid Fe-Cu alloy
HaiPeng Wang,BingBo Wei
Chinese Science Bulletin , 2011, DOI: 10.1007/s11434-011-4739-x
Abstract: Using liquid Fe60Cu40 alloy as a model, the structure of liquid Fe-Cu alloy systems is investigated in the temperature range 1200–2200 K, covering a large metastable undercooled regime, to understand the phase separation of liquid Fe-Cu alloys on the atomic scale. The total pair distribution functions (PDFs) indicate that liquid Fe60Cu40 alloy is ordered in the short range and disordered in the long range. If the atom types are ignored, the total atom number densities and PDFs demonstrate that the atoms are distributed homogenously in the liquid alloy. However, the segregation of Fe and Cu atoms is very obvious with decreasing temperature. The partial PDFs and coordination numbers show that the Cu and Fe atoms are not apt to get together on the atomic scale at low temperatures; this will lead to large fluctuations and phase separation in liquid Fe-Cu alloy.
Core-shell microstructure formed in the ternary Fe-Co-Cu peritectic alloy droplet
FuPing Dai,BingBo Wei
Chinese Science Bulletin , 2009, DOI: 10.1007/s11434-009-0103-9
Abstract: The metastable liquid phase separation occurs in the ternary Cu50Fe37.5Co12.5 peritectic alloy droplets during free fall. The separated alloy melt rapidly solidifies and evolves core-shell microstructure composed of L1(Cu) and L2(Fe,Co) phases. Based on the determination of the phase transition temperature, the core-shell microstructure evolution, the interfacial energy, the temperature gradient and the Marangoni migration are analyzed. The interfacial energy of the separated liquid phase increases with the decrease of the temperature. The temperature gradient changes from large to small along the radius direction from inside to outside in the alloy droplet. The Marangoni force (F M) acting on the micro-droplet of L2(Fe,Co) phase increases with the increase of the size of the L2(Fe,Co) phase, and decreases with the increase of undercooling. Driven by F M, the micro-droplet of L2(Fe,Co) phase migrates from outside to inside in the alloy droplet, collides and coagulates each other during migration, and then forms different types of core-shell microstructures.
Core-shell microstructure formed in the ternary Fe-Co-Cu peritectic alloy droplet

FuPing Dai,BingBo Wei,

科学通报(英文版) , 2009,
Abstract: The metastable liquid phase separation occurs in the ternary Cu50Fe37.5Co12.5 peritectic alloy droplets during free fall. The separated alloy melt rapidly solidifies and evolves core-shell microstructure composed of L1(Cu) and L2(Fe,Co) phases. Based on the determination of the phase transition temperature, the core-shell microstructure evolution, the interfacial energy, the temperature gradient and the Marangoni migration are analyzed. The interfacial energy of the separated liquid phase increases with the decrease of the temperature. The temperature gradient changes from large to small along the radius direction from inside to outside in the alloy droplet. The Marangoni force (F M) acting on the micro-droplet of L2(Fe,Co) phase increases with the increase of the size of the L2(Fe,Co) phase, and decreases with the increase of undercooling. Driven by F M, the micro-droplet of L2(Fe,Co) phase migrates from outside to inside in the alloy droplet, collides and coagulates each other during migration, and then forms different types of core-shell microstructures. Supported by the National Natural Science Foundation of China (Grant Nos. 50121101, 50395105) and NPU Youth Scientific and Technological Innovation Foundation (Grant No. W016223)
Separation and Determination of Eight Plant Hormones by Reversed Phase High Performance Liquid Chromatography
植物激素的反相高效液相色谱法分离和测定

Fang Nenghu,Hou Shuquan,Shao Xueguang,He Youzhao,Zhao Guiwen,
方能虎
,侯树泉,邵学广,何友昭,赵贵文

色谱 , 1998,
Abstract: 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.
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