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Search Results: 1 - 10 of 111901 matches for " Ivonete O.;Katime "
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Influência do comon?mero e do método de polimeriza??o na cinética de libera??o de fenobarbitona a partir de hidrogéis
Barcellos, Ivonete O.;Katime, Issa A.;Soldi, Valdir;Pires, Alfredo T. Nunes;
Polímeros , 2000, DOI: 10.1590/S0104-14282000000200013
Abstract: the release of water-soluble drugs from initially hydrated hydrogels matrices generally involves the simultaneous water absorption and drug desorption through a swelling-controlled diffusion mechanism. the diffusional behaviour of phenobarbitone from a hydrogel formed by a 2-hydroxyethylmethacrylate (hema) and methyl monoitaconate (mmi) copolymer was reported. the drug release into water was performed by high pressure liquid cromatography and the results showed that the phenobarbitone release from the hydrogels studies, considering the diffusion coefficient values did not change with the temperature and the polymerization method. the activation energy values suggested a more favorable phenobarbitone release from the hydrogels p(hema-co-mmi) polymerized in mass and bulk solution.
Influência do comon mero e do método de polimeriza o na cinética de libera o de fenobarbitona a partir de hidrogéis
Barcellos Ivonete O.,Katime Issa A.,Soldi Valdir,Pires Alfredo T. Nunes
Polímeros , 2000,
Abstract: A libera o de drogas solúveis em água a partir de matrizes de hidrogéis hidratados, geralmente envolve simultaneamente a absor o de água e a libera o da droga via mecanismo de difus o controlada. Foi analisado o comportamento difusional da fenobarbitona no hidrogel do copolímero 2-hidroxietil metacrilato (HEMA) e monoitaconato de metila (MMI). A libera o da droga no meio aquoso foi acompanhada por cromatografia líquida de alta press o e os resultados mostraram que a libera o da fenobarbitona a partir dos hidrogéis estudados, considerando-se os valores dos coeficientes de difus o, n o variou com a temperatura e com o método de polimeriza o. Os valores de energia de ativa o sugerem um favorecimento na libera o da fenobarbitona a partir dos hidrogéis de p(HEMA-co-MMI) polimerizados em massa e em solu o.
Chemical analysis of giant stars in the young open cluster NGC 3114
O. J. Katime Santrich,C. B. Pereira,N. A. Drake
Physics , 2013, DOI: 10.1051/0004-6361/201220252
Abstract: Context: Open clusters are very useful targets for examining possible trends in galactocentric distance and age, especially when young and old open clusters are compared. Aims: We carried out a detailed spectroscopic analysis to derive the chemical composition of seven red giants in the young open cluster NGC 3114. Abundances of C, N, O, Li, Na, Mg, Al, Ca, Si, Ti, Ni, Cr, Y, Zr, La, Ce, and Nd were obtained, as well as the carbon isotopic ratio. Methods: The atmospheric parameters of the studied stars and their chemical abundances were determined using high-resolution optical spectroscopy. We employed the local-thermodynamic-equilibrium model atmospheres of Kurucz and the spectral analysis code MOOG. The abundances of the light elements were derived using the spectral synthesis technique. Results: We found that NGC 3114 has a mean metallicity of [Fe/H] = -0.01+/-0.03. The isochrone fit yielded a turn-off mass of 4.2 Msun. The [N/C] ratio is in good agreement with the models predicted by first dredge-up. We found that two stars, HD 87479 and HD 304864, have high rotational velocities of 15.0 km/s and 11.0 km/s; HD 87526 is a halo star and is not a member of NGC 3114. Conclusions: The carbon and nitrogen abundance in NGC 3114 agree with the field and cluster giants. The oxygen abundance in NGC 3114 is lower compared to the field giants. The [O/Fe] ratio is similar to the giants in young clusters. We detected sodium enrichment in the analyzed cluster giants. As far as the other elements are concerned, their [X/Fe] ratios follow the same trend seen in giants with the same metallicity.
Swelling Properties of New Hydrogels Based on the Dimethyl Amino Ethyl Acrylate Methyl Chloride Quaternary Salt with Acrylic Acid and 2-Methylene Butane-1,4-Dioic Acid Monomers in Aqueous Solutions  [PDF]
Issa Katime, Eduardo Mendizábal
Materials Sciences and Applications (MSA) , 2010, DOI: 10.4236/msa.2010.13026
Abstract: Hydrogels of dimethylaminoethyl acrylate methyl chloride quaternary salt (Q9) have been synthesized with different monomer ratio by copolymerization of this poorly studied monomer either with acrylic acid or with 2-methylene bu-tane-1,4-dioic acid. Hydrogel swelling was measured as a function of the composition of the hydrogel and of the crosslinking agent ratio. High values of swelling have been obtained at very high crosslinking values (< 14 wt %) and the equilibrium swelling was reached at very low time (less than 15 minutes). The swelling isotherms consisted of a steep initial portion and then levelled off as asymptotically to the equilibrium swelling limit. The experimental data suggest clearly that the swelling process obeys second-order kinetics. According to this, the kinetics rate constant and the equilibrium water content were determined at different comonomer composition and crosslinker concentration. The calculated kinetic constants ranged from 0.48 to 3.76 × 10-2 min-1 for poly (acrylic acid-co-Q9) hydrogels and from 0.68 to 4.0 × 10-2 min-1 for poly (2-methylene butane-1,4-dioic acid-co-Q9) hydrogels depending on the hydrogels composition. The diffusion process was evaluated for each hydrogel showing a non-Fickian type diffusion. In all cases was observed a considerable increase in diffusion coefficient as Q9 content increases.
O fato e a fantasia: imagens dissimuladamente documentais que se revelam fic o
Pinto, Ivonete
Sess?es do Imaginário , 2005,
Abstract: O texto procura desvendar a estratégia retórica operacional do cineasta iraniano Abbas Kiarostami e, para tanto, abre a discuss o sobre a fronteira existente entre fic o e realidade, trabalhando algumas nuances do gênero documental. O artigo explora a complexidade das obras do cineasta, investigando como ele manipula o artifício que emerge da organiza o narrativa. The text aims uncovers the operational rhetoric strategic of the cineaste Iranian Abbas Kiarostami and, for in such a way, it opens discussion about the frontier between the fiction and reality, working some shades of the documentary gender. The paper explores the complexity of the work of the cineaste, inquiring into how he manipulates the artifice that emerges out of the narrative organization.
Blenda de náilon-6,6/quitosana como adsorvente de corantes ácidos para reutiliza??o das solu??es de corantes tratadas em tingimentos de poliamida
Barcellos, Ivonete O.;Andreaus, Jürgen;Battisti, Ana M.;Borges, Josélia K.;
Polímeros , 2008, DOI: 10.1590/S0104-14282008000300006
Abstract: water is used in the textile industry, mainly, as vehicle for chemicals and dyes used in the dyeing and finishing processes of textile fibers. in this work we studied the reuse of wastewater generated in the dyeing of nylon 6.6 (pa6.6) fabrics and treated by adsorption process with nylon 6.6/chitosan (80/20) blend flakes was studied. to produce the wastewater pa 6.6 fabrics were dyed with the acid dyes yellow erionyl rxl, red erionyl a-3b and navy blue erionyl r. the efficiency in color removal of the adsorption process varied between 97-98%, with exception of the effluents from yellow erionyl rxl dyeing, where only efficiencies of 65% (wastewater with auxiliaries) and 72% (without auxiliaries) were obtained. the reuse of the treated wastewater was studied in dyeing of knitted nylon 6.6 fabrics with the same dyes. δe values (color difference relative to a standard dyeing with distilled water) of the dyeings with light and medium colors varied from 0.24 to 1.05 for the wastewater of monochrome dyeing, and from 0.71 to 1.07 for the wastewater of trichrome dyeing and are compatible with industrial standards (δe < 1.1). it could be concluded that the reuse of treated wastewater from polyamide dyeing under the tested conditions is feasible, although with some restrictions for yellow especially.
Incorpora??o de lodo industrial em compósitos de resina poliéster
Barcellos, Ivonete O.;Souza, Ant?nio C. de;Selke, Anna E.;
Polímeros , 2009, DOI: 10.1590/S0104-14282009000200014
Abstract: the incorporation of industrial sludge (l) and chrysotile fiber (fc) in the preparation of composites with polyester resin (p) is a possible alternative to minimize the accumulation of solid wastes. the characterization of the structural composites with these reinforcements indicated reduction in density values when compared with glass fiber reinforced composites the maximum and minimum values of izod impact resistance for p/l/fc formulations were 29.1 and 12.6 j.m-1. the incorporation of sludge led to an increased thermal isolation capability for composites with crysotile fiber, also preserving the thermal stability of the polymeric matrix. the results indicated that although there are damages in mechanical properties, the incorporation of sludge in composites with polyester matrix results in mils with reduced density and low thermal conductivity.
Aplica??o de ciclodextrinas em processos têxteis
Andreaus, Jürgen;Dalmolin, Mara C.;Oliveira Junior, Iguatemy B. de;Barcellos, Ivonete O.;
Química Nova , 2010, DOI: 10.1590/S0100-40422010000400031
Abstract: cyclodextrins (cds) are water soluble cyclic sugars with a hydrophobic nanometric cavity that permits the formation of host/guest inclusion complexes with a large variety of molecules, alternating their physical-chemical properties. in the present review cd research related to the processing of textiles is revised and discussed. cds may function as encapsulating, dispersing and levelling agents in the dyeing and washing of textiles. furthermore they may be anchored to polymers and textile fibers in order to impart special properties such as odor reduction, uv protection or for the controlled release of perfumes, aromas, mosquito repellents or substances with therapeutical effects.
Adapta??o no método do peso da gota para determina??o da tens?o superficial: um método simplificado para a quantifica??o da CMC de surfactantes no ensino da química
Behring, Jo?o Lino;Lucas, M?nica;Machado, Clodoaldo;Barcellos, Ivonete Oliveira;
Química Nova , 2004, DOI: 10.1590/S0100-40422004000300021
Abstract: the discussion based on surfactant cleaning action is commonly used in chemistry classrooms for the comprehension of theoretical concepts related to surface tension and micelle formation. the experimental quantification of surface tension of aqueous solutions of surfactants provides the practical instruments for this discussion. the present paper describes a simplification on the common apparatus employed for the drop-weight method, making the determination of surface tension accessible to any chemistry lab. the surface tension of various liquids and the critical micelle concentration, cmc, of three commercial surfactants were measured with this modified method, and proved to be consistent with literature values.
Adapta o no método do peso da gota para determina o da tens o superficial: um método simplificado para a quantifica o da CMC de surfactantes no ensino da química
Behring Jo?o Lino,Lucas M?nica,Machado Clodoaldo,Barcellos Ivonete Oliveira
Química Nova , 2004,
Abstract: The discussion based on surfactant cleaning action is commonly used in chemistry classrooms for the comprehension of theoretical concepts related to surface tension and micelle formation. The experimental quantification of surface tension of aqueous solutions of surfactants provides the practical instruments for this discussion. The present paper describes a simplification on the common apparatus employed for the drop-weight method, making the determination of surface tension accessible to any chemistry lab. The surface tension of various liquids and the critical micelle concentration, CMC, of three commercial surfactants were measured with this modified method, and proved to be consistent with literature values.
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