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## Phase diagrams of a CTAB/organic solvent/buffer system applied to extraction of enzymes by reverse micelles

FEITOSA, E.; CATELAM, K. T.; HASMANN, F. A.; JOHANSSON, Hans-Olof; ROBERTO, I. C.; PESSOA JR., A.
Fonte: ELSEVIER SCIENCE BV Publicador: ELSEVIER SCIENCE BV
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
56.11%
A partial pseudo-ternary phase diagram has been studied for the cethyltrimethylammonium bromide/isooctane:hexanol:butanol/potassium phosphate buffer system, where the two-phase diagram consisting of the reverse micelle phase (L-2) in equilibrium with the solvent is indicated. Based on these diagrams two-phase systems of reverse micelles were prepared with different compositions of the compounds and used for extraction and recovery of two enzymes, and the percentage of enzyme recovery yield monitored. The enzymes glucose-6-phosphate dehydrogenase (G6PD) and xylose redutase (XR) obtained from Candida guilliermondii yeast were used in the extraction procedures. The recovery yield data indicate that micelles having different composition give selective extraction of enzymes. The method can thus be used to optimize enzyme extraction processes. (c) 2007 Elsevier B.V. All rights reserved.

## Phase behavior of the orange essential oil/sodium bis(2-ethylhexyl)sulfosuccinate/water system

Feitosa, Eloi da Silva; CAVALCANTE, Vanessa R. O.; Amaral, Lia Queiroz do
Fonte: ELSEVIER SCIENCE BV Publicador: ELSEVIER SCIENCE BV
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
56.05%
The ternary phase diagram for the orange essential oil (OEO)/sodium bis(2-ethylhexyl)sulfosuccinate (AOT)/water system was constructed at 25 degrees C. It indicates a large single phase region, comprising an isotropic water-in-oil (W/O) microemulsion (ME) phase (L(2)), a liquid crystal (LC) (lamellar or hexagonal) and a large unstable emulsion phase that separates in two phases of normal and reverse micelles (L(1) and L(2)). In this communication the properties of the ME are investigated by viscosity, electric conductivity and small angle X-ray scattering (SAXS) indicating that the isotropic ME phase exhibits different behaviors depending on composition. At low water content low viscous ""dry"" surfactant structures are formed, whereas at higher water content higher viscous water droplets are formed. The experimental data allow the determination of the transition from ""dry"" to the water droplet structures within the L(2) phase. SAXS analyses have also been performed for selected LC samples. (C) 2009 Elsevier B.V. All rights reserved.; FAPESP; Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); CNPq; Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

## Ab initio calculation of the BCC Fe-Al-Mo (Iron-Aluminum-Molybdenum) phase diagram: Implications for the nature of the tau(2) phase

Santos, Ney Sodré dos; GONZALES-ORMENO, Pablo Guillermo; Petrilli, Helena Maria; Schon, Claudio Geraldo
Fonte: PERGAMON-ELSEVIER SCIENCE LTD Publicador: PERGAMON-ELSEVIER SCIENCE LTD
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
56.04%
The metastable phase diagram of the BCC-based ordering equilibria in the Fe-Al-Mo system has been calculated via a truncated cluster expansion, through the combination of Full-Potential-Linear augmented Plane Wave (FP-LAPW) electronic structure calculations and of Cluster Variation Method (CVM) thermodynamic calculations in the irregular tetrahedron approximation. Four isothermal sections at 1750 K, 2000 K, 2250 K and 2500 K are calculated and correlated with recently published experimental data on the system. The results confirm that the critical temperature for the order-disorder equilibrium between Fe(3)Al-D0(3) and FeAl-B2 is increased by Mo additions, while the critical temperature for the FeAl-B2/A2 equilibrium is kept approximately invariant with increasing Mo contents. The stabilization of the Al-rich A2 phase in equilibrium with overstoichiometric B2-(Fe,Mo)Al is also consistent with the attribution of the A2 structure to the tau(2) phase, stable at high temperatures in overstoichiometric B2-FeAl. (C) 2009 Elsevier Ltd. All rights reserved.; Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Sao Paulo State Research Funding Agency (FAPESP, Sao Paulo-SP, Brazil)[2006/02470-0]; Brazilian National Research Council (CNPq...

## Enhancement of Nematic Order and Global Phase Diagram of a Lattice Model for Coupled Nematic Systems

Liarte, Danilo Barbosa; Salinas, Silvio Roberto de Azevedo
Fonte: SPRINGER; NEW YORK Publicador: SPRINGER; NEW YORK
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
56.09%
We use an infinite-range Maier-Saupe model, with two sets of local quadrupolar variables and restricted orientations, to investigate the global phase diagram of a coupled system of two nematic subsystems. The free energy and the equations of state are exactly calculated by standard techniques of statistical mechanics. The nematic-isotropic transition temperature of system A increases with both the interaction energy among mesogens of system B, and the two-subsystem coupling J. This enhancement of the nematic phase is manifested in a global phase diagram in terms of the interaction parameters and the temperature T. We make some comments on the connections of these results with experimental findings for a system of diluted ferroelectric nanoparticles embedded in a nematic liquid-crystalline environment.; FAPESP; Fapesp; CNPq; CNPq

## Estudo experimental do diagrama de fase do MnP na região dos pontos de encontro entre as fases moduladas e a fase ferromagnética; Experimental study of the MnP phase diagram in the region of the meeting points between modulated phases and ferromagnetic phase

Migliano, Antonio Carlos da Cunha
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 31/03/1989 PT
Relevância na Pesquisa
66.13%

## Determinação dos diagramas de fases do sistema Fe-Al-Mo cúbico de corpo centrado por cálculos de primeiros princípios; Determination of the phase diagrams of the body-centered cubic system Fe-Al-Mo by first-principles calculations.

Ormeño, Pablo Guillermo Gonzáles
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 24/10/2002 PT
Relevância na Pesquisa
56.04%

## Phase diagrams of a CTAB/organic solvent/buffer system applied to extraction of enzymes by reverse micelles

Feitosa, E.; Catelam, K. T.; Hasmann, F. A.; Johansson, Hans-Olof; Roberto, I. C.; Pessoa, A.
Fonte: Elsevier B.V. Publicador: Elsevier B.V.
Tipo: Artigo de Revista Científica Formato: 58-63
ENG
Relevância na Pesquisa
56.11%
A partial pseudo-ternary phase diagram has been studied for the cethyltrimethylammonium bromide/isooctane:hexanol:butanol/potassium phosphate buffer system, where the two-phase diagram consisting of the reverse micelle phase (L-2) in equilibrium with the solvent is indicated. Based on these diagrams two-phase systems of reverse micelles were prepared with different compositions of the compounds and used for extraction and recovery of two enzymes, and the percentage of enzyme recovery yield monitored. The enzymes glucose-6-phosphate dehydrogenase (G6PD) and xylose redutase (XR) obtained from Candida guilliermondii yeast were used in the extraction procedures. The recovery yield data indicate that micelles having different composition give selective extraction of enzymes. The method can thus be used to optimize enzyme extraction processes. (c) 2007 Elsevier B.V. All rights reserved.

## Phase behavior of the orange essential oil/sodium bis(2-ethylhexyl)sulfosuccinate/water system

Feitosa, Eloi; Cavalcante, Vanessa R. O.; Amaral, Lia Q.
Fonte: Elsevier B.V. Publicador: Elsevier B.V.
Tipo: Artigo de Revista Científica Formato: 82-86
ENG
Relevância na Pesquisa
56.05%
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); The ternary phase diagram for the orange essential oil (OEO)/sodium bis(2-ethylhexyl)sulfosuccinate (AOT)/water system was constructed at 25 degrees C. It indicates a large single phase region, comprising an isotropic water-in-oil (W/O) microemulsion (ME) phase (L(2)), a liquid crystal (LC) (lamellar or hexagonal) and a large unstable emulsion phase that separates in two phases of normal and reverse micelles (L(1) and L(2)). In this communication the properties of the ME are investigated by viscosity, electric conductivity and small angle X-ray scattering (SAXS) indicating that the isotropic ME phase exhibits different behaviors depending on composition. At low water content low viscous "dry" surfactant structures are formed, whereas at higher water content higher viscous water droplets are formed. The experimental data allow the determination of the transition from "dry" to the water droplet structures within the L(2) phase. SAXS analyses have also been performed for selected LC samples. (C) 2009 Elsevier B.V. All rights reserved.

## Short-chain di-ureasil ormolytes doped with potassium triflate: Phase diagram and conductivity behavior

De Zea Bermudez, V.; Gomes Correia, S. M.; Silva, M. M.; Barros, S.; Smith, M. J.; Sá Ferreira, R. A.; Carlos, L. D.; Molina, C.; Ribeiro, S. J L
Tipo: Conferência ou Objeto de Conferência Formato: 375-381
ENG
Relevância na Pesquisa
66.07%
Di-urea cross-linked poly(oxyethylene)/siloxane hybrids, synthesized by the sol-gel process and containing a wide concentration range of potassium triflate, KCF3SO3, have been analyzed by x-ray diffraction and differential scanning calorimetry. The pseudo-phase diagram proposed has been taken into account in the interpretation of the complex impedance measurements. The xerogels prepared are obtained as transparent, thin monoliths. At room temperature the highest conductivity found was 2 × 10-6 Ω-1 cm-1.

## Short-chain U(600) di-ureasil ormolytes doped with potassium triflate : phase diagram and conductivity behavior

Zea Bermudez, V. de; Correia, M. Gomes; Silva, Maria Manuela; Barros, Sandra Cerqueira; Smith, Michael John; Ferreira, R. A. Sá; Carlos, L. D.; Molina, C.; Ribeiro, A. J. L.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em //2003 ENG
Relevância na Pesquisa
66.04%
Di-urea cross-linked poly(oxyethylene)/siloxane hybrids, synthesized by the sol-gel process and containing a wide concentration range of potassium triflate, KCF3SO3, have been analyzed by x-ray diffraction and differential scanning calorimetry. The pseudo-phase diagram proposed has been taken into account in the interpretation of the complex impedance measurements. The xerogels prepared are obtained as transparent, thin monoliths . At room temperature the highest conductivity found was 2 x 10-6Scm-1.; Fundação para a Ciência e a Tecnologia (FCT)

## The phase diagram of the betaine arsenate-phosphate mixed crystal system by measurement of the dielectric hysteresis and current curves

Lanceros-Méndez, S.; Köhler, M.; Schaack, G.; Klöpperpieper, A.
Fonte: American Physical Society Publicador: American Physical Society
Tipo: Artigo de Revista Científica
Publicado em //2006 ENG
Relevância na Pesquisa
66.26%
The ferroelectric (FE) betaine arsenate (BA) and the antiferroelectric (AF) betaine phosphate (BP) are structurally very closely related and mixed crystals of BAxBP1-x can be grown over the whole concentration range. The concentration (x) – temperature (T) – pressure (P) phase diagram of the system is characterized by a transition from an AF to a FE phase along with the appearance of some mixed regions on changing concentration. Depending on concentration, one or two relaxation processes appear in the low temperature region of the phase diagram. Measurement of the hysteresis loops and the current curves have been carried out along the (x-T-P)-phase diagram of this system. Multiple loops have been observed in various regions of the phase diagram. The correlation of the different contributions of the polarization and the temperature behavior of their critical fields with the main features of the temperature and frequency dependent dielectric constant enables clarification of the rich phase diagram obtained in this mixed compounds in terms of the ferro- and/or antiferroelectric interactions.

## X-DLVO Interactions between nanocolloidal magnetic particles: the quantitative interpretation of the pH-dependent phase diagram of EDL-MF

Campos,A. F. C.; Marinho,E. P.; Ferreira,M. de A.; Tourinho,F. A.; Paula,F. L. de O.; Depeyrot,J.
Fonte: Sociedade Brasileira de Física Publicador: Sociedade Brasileira de Física
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/04/2009 EN
Relevância na Pesquisa
56.09%
The phase behavior of acidic samples of EDL-MF based on cobalt ferrite nanoparticles with controlled mean sizes was investigated at constant temperature and in absence of magnetic field. By monitoring the nanoparticle charge by pH adjustments, we constructed an experimental pH-dependent phase diagram for all samples that revealed sol, gel thixotropic or coagulated phases in different pH regions. Then, by using an extended DLVO potential we analyzed quantitatively the observed phase diagram in function of pH and nanoparticle mean size.

## Ternary phase diagram of ketamine ((R,S)-2-(2-chlorophenyl)-2methylaminocyclohexanone) in ethanol and preliminary studies aiming at Enantioselective Crystallization of S-ketamine

Barros,G. O. F.; Tamagawa,R. E.; Santana,C. C.; Miranda,E. A.
Fonte: Brazilian Society of Chemical Engineering Publicador: Brazilian Society of Chemical Engineering
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2009 EN
Relevância na Pesquisa
56.07%
Crystallization is an important industrial-scale process for the purification of enantiomers that depends on a phase diagram. In this work, the ternary phase diagram of R- and S-ketamine in ethanol was determined. The eutectic point indicated that crystallization of pure enantiomers from solutions containing more than 75% of the desired enantiomer is feasible. Solubility studies showed the feasibility of using temperature control to conduct the process. Batch crystallization of ketamine (S/R:80/20) solutions at 25ºC provided the isolation of S-ketamine (purity of 100%) with a yield from 65 to 70% and a productivity of 6.5 g/(lh).

## An extended high pressure-temperature phase diagram of NaBH4

George, Lyci; Drozd, Vadym; Couvy, Helene; Chen, Jiuhua; Saxena, Surendra K.
Fonte: American Institute of Physics Publicador: American Institute of Physics
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
56.11%
We have studied the structural stability of NaBH4 under pressures up to 17 GPa and temperatures up to 673 K in a diamond anvil cell and formed an extended high P-T phase diagram using combined synchrotron x-ray diffraction and Raman spectroscopy. Even though few reports on phase diagram of NaBH4 are found in current literature, up to our knowledge this is the first experimental work using diamond anvil cell in a wide pressure∕temperature range. Bulk modulus, its temperature dependence, and thermal expansion coefficient for the ambient cubic phase of NaBH4 are found to be 18.76(1) GPa, −0.0131 GPa K−1, and 12.5×10−5+23.2×10−8 T∕K, respectively. We have also carried out Raman spectroscopic studies at room temperature up to 30 GPa to reinvestigate the phase transitions observed for NaBH4. A comparative symmetry analysis also has been carried out for different phases of NaBH4.

## Quantum Criticality and the Phase Diagram of the Cuprates

Sachdev, Subir
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
EN_US
Relevância na Pesquisa
56.07%
I discuss a proposed phase diagram of the cuprate superconductors as a function of temperature, carrier concentration, and a strong magnetic field perpendicular to the layers. I show how the phase diagram gives a unified interpretation of a number of recent experiments.; Physics

## Phase diagram of a two-dimensional lattice gas model of a ramp system

García Almarza, Noé; Capitán, José A.; Cuesta, José A.; Lomba, Enrique
Fonte: American Institute of Physics Publicador: American Institute of Physics
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 28/09/2009 ENG
Relevância na Pesquisa
56.11%
Using Monte Carlo simulation and fundamental measure theory we study the phase diagram of a two-dimensional lattice gas model with a nearest neighbor hard core exclusion and a next-to-nearest neighbor finite repulsive interaction. The model presents two competing ranges of interaction and, in common with many experimental systems, exhibits a low density solid phase, which melts back to the fluid phase upon compression. The theoretical approach is found to provide a qualitatively correct picture of the phase diagram of our model system.; We acknowledge the support from Dirección General de Investigación Científica y Técnica under Project No. MAT2007-65711-C04-04 (N.G.A. and E.L.) and MOSAICO (J.A.C. and J.A.C.), and the Dirección General de Universidades e Investigación de la Comunidad de Madrid under project MOSSNOHO-CM (Grant No. S0505/ESP/0299). J.A. Capitán is supported by a contract from Comunidad de Madrid and Fondo Social Europeo.; 12 pages, 7 figures.-- PACS nrs.: 61.20.Gy, 65.20.-w.-- ArXiv pre-print available at: http://arxiv.org/abs/0907.3447; Final publisher version available Open Access at: http://gisc.uc3m.es/~cuesta/papers-year.html

## Phase diagram of a two-dimensional lattice gas model of a ramp system

Almarza, Noé G.; Capitán, J. A.; Cuesta, J. A.; Lomba, Enrique
Fonte: American Institute of Physics Publicador: American Institute of Physics
Tipo: Artículo Formato: 318444 bytes; application/pdf
ENG
Relevância na Pesquisa
66.16%
Using Monte Carlo simulation and fundamental measure theory we study the phase diagram of a two-dimensional lattice gas model with a nearest neighbor hard core exclusion and a next-to-nearest neighbor finite repulsive interaction. The model presents two competing ranges of interaction and, in common with many experimental systems, exhibits a low density solid phase, which melts back to the fluid phase upon compression. The theoretical approach is found to provide a qualitatively correct picture of the phase diagram of our model system; Direcci´on General de Investigaci´on Cient´ıfica y T´ecnica under projects no. MAT2007-65711-C04-04 (N.G.A. and E.L.) and MOSAICO (J.A.C. and J.A.C.), and the Direcci´on General de Universidades e Investigaci´on de la Comunidad de Madrid under project MOSSNOHO-CM (S0505/ESP/0299). J. A. Capit´an is supported by a contract from Comunidad de Madrid and Fondo Social Europeo; Peer reviewed

## Phase diagram of silicon from atomistic simulations

Kaczmarski, Marcin; Bedoya-Martinez, O. Natalia; Hernández, Eduardo R.
Fonte: American Physical Society Publicador: American Physical Society
Tipo: Artículo Formato: 120810 bytes; application/pdf
ENG
Relevância na Pesquisa
56.09%
http://scitation.aip.org/vsearch/servlet/VerityServlet?KEY=PRLTAO&smode=strresults&sort=rel&maxdisp=25&threshold=0&allprl=1&pjournals=PRLTAO&pyears=aps2000s&possible1zone=multi&bool1=and&possible2=Kaczmarski&possible2zone=author&OUTLOG=NO&articlecategory=apsAllarticles&viewabs=PRLTAO&key=DISPLAY&docID=1&page=1&chapter=0; In this letter we present a calculation of the temperature-pressure phase diagram of Si in a range of pressures covering from $-5$ to 20~GPa and temperatures up to the melting point. The phase boundaries and triple points between the diamond, liquid, $\beta$-Sn and $\mbox{Si}_{34}$ clathrate phases are reported. We have employed efficient simulation techniques to calculate free energies and to numerically integrate the Clausius-Clapeyron equation, combined with a tight binding model capable of an accuracy comparable to that of first-principles methods. The resulting phase diagram agrees well with the available experimental data.; The use of computer facilities at $C^4$ (Centre de Computaci\{o} i Comunicaci\{o} de Catalunya), CESGA (CEntro de Supercomputaci\'{o}n de GAlicia), ICM (Interdisciplinary Center for Mathematical and Computer Modeling, Warsaw University), and TASK (Academic Computer Center...

## Data for "Quantum Monte Carlo study of the phase diagram of solid molecular hydrogen at extreme pressures"

Drummond, N. D.; Monserrat, Bartomeu; Lloyd-Williams, Jonathan H.; Lopez Rios, P.; Pickard, Chris J.; Needs, R. J.