Solu����es cosmol��gicas e locais para uma eletrodin��mica modificada

The present work investigates some consequences that arise from the use of a modifed lagrangean for the eletromagnetic feld in two diferent contexts: a spatially homogeneous and isotropic universe whose dynamics is driven by a magnetic feld plus a cosmological parameter A, and the problem of a static and charged point mass (charged black hole). In the cosmological case, three diferent general solutions were derived. The first, with a null cosmological parameter A, generalizes a particular solution obtained by Novello et al [gr-qc/9806076]. The second one admits a constant A and the third one allows A to be a time-dependent parameter that sustains a constant magnetic feld. The first two solutions are non-singular and exhibit in ationary periods. The third case studied shows an in ationary dynamics except for a short period of time. As for the problem of a charged point mass, the solutions of the Einstein-Maxwell equations are obtained and compared with the standard Reissner-Nordstrom solution. Contrary to what happens in the cosmological case, the physical singularity is not removed

An��lise do potencial genot��xico da superf��cie de tit��nio modificada por plasma

Coordena����o de Aperfei��oamento de Pessoal de N��vel Superior

Fluxo de pot��ncia ��timo reativo via m��todo da fun����o lagrangiana barreira modificada

Funda����o de Amparo �� Pesquisa do Estado de S��o Paulo (FAPESP)

Resolvendo problemas de fluxo de pot��ncia ��timo DC atrav��s de uma rede de hopfield modificada

Funda����o de Amparo �� Pesquisa do Estado de S��o Paulo (FAPESP)

Hidr��lise e caracteriza����o de poliacrilamida hidrofobicamente modificada: avalia����o da aplicabilidade na recupera����o de petr��leo

The hydrolysis reaction in alkaline conditions of the commercial polymer poly(acrylamide-co-metacrylate of 3,5,5-trimethyl-hexane) called HAPAM, containing 0.75 % of hydrophobic groups, was carried out in 0.1 M NaCl and 0.25M NaOH solutions, varying the temperature and reaction time. The polymers were characterized by 1H and 13C Nuclear Magnetic Resonance (NMR), Elemental Analysis and Size Exclusion Chromatography (SEC). The values of the hydrolysis degree were obtained by 13C NMR. The viscosity of HAPAM and HAPAM-10N-R solutions was evaluated as a function of shear rate, ionic strength and temperature. At high polymer concentration (Cp), the viscosity of HAPAM solutions increased with the ionic strength and decreased with the temperature. The viscosity of HAPAM-10N-R solutions increased significantly in distilled water, due to repulsions between the carboxylate groups. At high Cp, with the increase of ionic strength and temperature, occurred a decrease of viscosity, due to mainly the high hydrolysis degree and the low amount of hydrophobic groups. These results indicated that the studied polymers have properties more suitable for the application in Enhanced Oil Recovery (EOR) in low salinity and moderate temperature reservoirs

Aplica����o de argila branca comercial pura e modificada para adsor����o de sulfeto de hidrog��nio

In this work were synthesized matrix-based commercial white clay in its composition having large amounts of kaolinite and quartz, with a certain percentage of iron oxide for use as an adsorbent for hydrogen sulfide (H2S). To characterize the effect of initial matrix techniques were used to characterize XRD, FTIR, XRF and TG. The initial clay mineral matrix was placed in contact with 0.1 molar solutions of the salts of Co2+, Ni2+, Cr3+ and a solution 0.1 g / 100ml rhodamine B. During the synthesis process, the solutions were placed in contact with the initial matrix for a period of 48 hours in order to have ion exchange with the clay mineral. To check the amount of exchanged metals, we used the technique of X-ray Fluorescence (XRF). After synthesis was initiated the process of adsorption of H2S, where the arrays were placed in the reactor, then by passing a stream of hydrogen sulfide. The matrix along with the reactor was weighed before and after to measure the amount of gas adsorbed. Based on the gravimetric data the matrix which had the highest performance of the adsorption matrix was exchanged with Ni2+ ions, obtaining a result of 11.13 mg H2S / g matrix, then the matrix coated with rhodamine B which was reached 10.13 mg H2S / g matrix

S��ntese, caracteriza��ao e propriedades catalicas da peneira molecular nanoestruturada modificada com lantanio

The nanostructured molecular sieve SBA-15 was synthesized by the hydrothermal method, and modified with lanthanum with Si/La molar ratios of 25, 50, 75 and 100. The materials were evaluated as catalysts for the cracking of n-hexane model reaction. Type SBA- 15 and LaSBA-15 mesoporous materials were synthesized using tetraetilortosilicato as a source of silica, hydrochloric acid, heptahydrate lanthanum chloride and distilled water. Pluronic P123 triblock. polymer was used as structure template. The syntheses were carried out by 72 hours. The obtained SBA-15 samples were previously analyzed by thermogravimetry, in order to check the conditions of calcination for removal of organic template. Then, the calcined materials were characterized by X-ray diffraction, infrared spectroscopy, adsorption and desorption of nitrogen, scanning electron microscopy and X-ray microanalysis by dispersive energy. The acidity of the samples was determined using adsorption of n-bulinamina and desorption followed by thermogravimetry. It was found that the hydrothermal synthesis method was suitable for the synthesis of the SBA-15 mesoporous materials, with an excellent degree of hexagonal ordering. The reactions of catalytic cracking of n-hexane were carried out using a fixed bed continuous flow microreactor, coupled on-line to a gas chromatograph. From the catalytic evaluation, it was observed that the mesoporous materials containing lanthanum showed different results for the reaction of cracking of nhexane compared to the unmodified mesoporous material SBA-15. As a result of cracking was obtained as main products hydrocarbons in the range of C1 to C5. The catalyst that showed better properties in relation to the acidity and catalytic activity was LaSBA-15 with the ratio Si/La = 50

Estudo comparativo entre a pir��lise do polietileno de baixa densidade, utilizando vermiculita modificada e SBA-15

Catalytic processes are widely present in everyday life. This results in large number of studies seeking materials that may combine the low cost catalytic efficiency. Based on this assumption, the clays have long been used as catalysts, with its huge availability, diversity and possibility of improving their properties from structural changes, primarily responsible for this great use. Among the natural clays, vermiculite due to their characteristic properties (high cation exchange capacity and expansion), is suitable for various applications including as catalysts and catalyst supports. In this work, the acid leaching of clay vermiculite was performed, coming from Santa Luzia-PB, with nitric acid (2, 3 and 4 mol / L) and subsequent calcination of the materials obtained. The materials were named as Vx/400, where x is the acid concentration employed and 400 used in calcination temperature. The effectiveness of changes made was determined by XRD techniques, FT-IR, EDS, TG/DTG, nitrogen physisorption and DTP of n-butylamine. Acid leaching has improved some properties of the clay - specific area and acidity - but the control of the acid concentration used is of vital importance, since the highest concentration caused the partial destruction of vermiculite entailing a decline in their properties. For analysis of the catalytic activity of the modified clay was made a comparative study with the SBA -15 mesoporous materials, synthesized via hydrothermal method, using the pyrolysis of low density polyethylene (LDPE). The results showed that the acid plays a fundamental role in the conversion of the polymer into smaller molecules, the material V3/400 was more selective for the source monomer (ethylene) due to their increased acidity, which promotes more breaks bonds in the polymeric chain, while materials and V0/400 V2/400, lower acidity, showed higher selectivity to light hydrocarbons, the range of fuel (41.96 and 41.23%, respectively), due to less breakage and secondary condensation reactions chains; already V4/400 SBA-15/550 and resulted in lower percentages of light hydrocarbons and the partial destruction of the structure and low acidity, respectively, responsible for the inefficiency of materials

Caracteriza����o e aplica����o de vermicultura natural e quimicamente modificada na adsor����o de azul de metileno

Chemical modification of clays has been extremely studied in the search for improvements of their properties for use in various areas, such as in combating pollution by industrial effluents and dyes. In this work, the vermiculite was chemically modified in two ways, characterized and evaluated the adsorption of methylene blue dye. First was changed with the addition of a surfactant (hexadecyltrimethylammonium bromide, BHTA) making it an organophilic clay and then by adding an acid (HCl) by acid activation. Some analyzes were performed as X-ray fluorescence (FRX), X-ray diffraction (DRX), adsorption isotherms of methylene blue dye, infrared (FTIR) , scanning electron microscopy (SEM), thermal gravimetric analysis and spectroscopy energy dispersive (EDS). Analysis by FRX of natural vermiculite indicates that addition of silicon and aluminum, clay presents in its structure the magnesium, calcium and potassium with 16 % organic matter cations. The DRX analyzes indicated that the organic vermiculite was an insertion of the surfactant in the space between the lamellae, vermiculite and acid partial destruction of the structure with loss of crystallinity. The adsorption isotherms of methylene blue showed that there was a significant improvement in the removal of dye to the vermiculite with the addition of cationic surfactant hexadecyltrimethylammonium bromide and treatment with acid using HCl 2 mol/L. In acid vermiculites subsequently treated with surfactant, the adsorption capacity increased with respect to natural vermiculite, however was much lower compared vermiculite modified with acid and surfactant separately. Only the acidic vermiculite treated with surfactant adjusted to the Langmuir model. As in the infrared spectrometry proved the characteristics of natural vermiculite. In the organic vermiculite was observed the appearance of characteristic bands of CH3, CH2, and (CH3)4N. Already on acid vermiculite, it was realized a partial destruction with decreasing intensity of the characteristic band of vermiculite that is between 1074 and 952 cm-1. In the SEM analysis, it was observed that there was partial destruction to the acid treatment and a cluster is noted between the blades caused by the presence of the surfactant. The TG shows that the higher mass loss occurs at the beginning of the heating caused by the elimination of water absorbed on the surface between layers. In the organic vermiculite also observed a loss of mass between 150 and 300 ��C caused decomposition of the alkylammonium molecules (surfactants)

Estudo retrospectivo de 11 casos de aerofagia em equinos operados pela t��cnica de miectomia de Forssell modificada

No presente trabalho foi feita unta revis��o do resultado p��s-operat��rio com a t��cnica de miectomia de Forssell modificada aplicada em 11 equinos portadores de aerofagia, atendidos no Hospital Veterin��rio da FMVZ-UNESP, Botucatu, no per��odo entre julho de 1992 e abril de 1995. A t��cnica consiste basicamente na ressec����o dos m��sculos omohio��deo, esternohio��deo e esternotirohio��deo associado �� neurectomia do ramo ventral do nervo acess��rio, que inerva o m��sculo esternomandibular. As informa����es sobre a evolu����o p��s-operat��ria. que variou entre 4 e 36 meses, foram obtidas por contacto telef��nico ou carta question��rio. As ra��as acometidas foram: Quarto de Milha (5 animais). Apaloosa (4 animais), Mangalarga (1 animal) e Brasileira de Hipismo (1 animal), sendo 7 f��meas e 4 machos, e as idades variaram entre 1,5 e 11 anos. O resultado p��s-operat��rio mostrou que 7 animais (63.3%) estavam totalmente recuperados; 2 animais (18.1%) recuperaram-se parcialmente pois o problema recidivou embora em menor intensidade entre 30 e 90 dias ap��s a cirurgia e 2 animais (18,1%) n��o tiveram nenhuma melhora.

Biomateriais: deposi����o de hidroxiapatita sobre superf��cie de Ti-cp modificada por aspers��o t��rmica

The osseointegrated titanium implants are reliable and safe alternatives to treatments for long periods of time. For surface modification, thermal aspersion of TiO2 was used. The samples with and without TiO2 were treated with NaOH and SBF in order to obtain a layer of HA. Characterization was done by SEM and FTIR. The images of HA obtained by SEM show a uniform morphology and a porous structure with spherical particles. The IR spectra show that the surface of Ticp/ TiO2 is more favorable for the HA deposit, as can be seen by the increase of the crystalline structure and the very intense and defined bands of the OH group of HA that is verified about 3571 and 630 cm-1. Thus the Ticp/ TiO2 surface presents a satisfactory nucleation of HA when compared to Ticp.

Compara����o de par��metros periodontais ap��s utiliza����o de conten����o ortod��ntica com fio tran��ado e conten����o modificada

OBJETIVO: o presente estudo teve como objetivo comparar dois tipos de conten����es ortod��nticas fixas, em rela����o a par��metros periodontais estabelecidos. A conten����o com fio tran��ado �� a mais comumente utilizada e a conten����o modificada apresenta dobras que t��m a finalidade de permitir o livre acesso do fio dental ��s ��reas interproximais. M��TODOS: para esse estudo cruzado, foram selecionados 12 volunt��rios que utilizaram, por 6 meses, A) Conten����o com fio tran��ado e B) Conten����o modificada - sendo essas fixadas em todos os dentes do segmento anterior. Ap��s esse per��odo experimental, foram feitas as seguintes avalia����es: ��ndice de Placa Dent��ria, ��ndice Gengival, ��ndice de C��lculo Dent��rio e ��ndice de C��lculo ao longo do fio de conten����o. Os volunt��rios tamb��m responderam a um question��rio com rela����o �� utiliza����o, conforto e higieniza����o das conten����es. RESULTADOS: foi observado que o ��ndice de placa e o ��ndice gengival foram maiores nas faces linguais (p<0,05) para a conten����o modificada. Al��m disso, o ��ndice de c��lculo foi estatisticamente maior (p<0,05) considerando-se as faces linguais e proximais na utiliza����o da conten����o modificada. O ��ndice de c��lculo ao longo do fio tamb��m apresentou valores significativamente maiores (p<0,05) na conten����o modificada. em rela����o ao question��rio, 58% dos volunt��rios consideraram que a conten����o modificada �� mais desconfort��vel; e 54% deles preferiram a conten����o com fio tran��ado. CONCLUS��O: a partir dos resultados obtidos, pode-se concluir que a conten����o com fio tran��ado apresentou melhores resultados do que a conten����o modificada, de acordo com os par��metros periodontais avaliados, al��m de apresentar maior conforto e prefer��ncia na sua utiliza����o.

Armazenagem em atmosfera modificada passiva de carambola azeda (Averrhoa carambola L.) cv. 'Golden Star'

Este trabalho avaliou o efeito das embalagens de polietileno de baixa densidade (PEBD), em diferentes espessuras, no prolongamento da vida ��til p��s-colheita de carambolas cv. 'Golden Star'. Os frutos foram colhidos fisiologicamente maturos, sendo selecionados pela aus��ncia de defeitos e acondicionados nas embalagens de PEBD, constituindo os seguintes tratamentos: T1 - controle (sem embalagem); T2 - PEBD de 6 mim; T3 - PEBD de 10 mim; T4 - PEBD de 15 mim. Os frutos foram armazenados a 12 +/- 0,5 ��C e 95 +/- 5% de UR, por 45 dias, e mais 5 dias a 22 +/- 3��C e 72 +/- 5% de UR. Vinte e quatro horas ap��s a colheita e a cada nove dias, amostras eram retiradas do armazenamento refrigerado (AR), mantidas por 12 horas em condi����es ambiente (22 +/- 3��C e 72 +/- 5% UR) e analisadas quanto �� firmeza de polpa (FP), �� perda de massa fresca, �� colora����o da epiderme, aos s��lidos sol��veis totais (SST), �� acidez total titul��vel (ATT) e �� ocorr��ncia de dist��rbios fisiol��gicos. Realizou-se tamb��m uma an��lise sensorial ao final do experimento. A maior firmeza de polpa e acidez total titul��vel, o melhor padr��o de colora����o, o menor conte��do de s��lidos sol��veis totais, a aus��ncia de manchas e podrid��es, e a melhor aceitabilidade pelos julgadores foram obtidos com os frutos acondicionados em embalagens de 10 mim.

Conserva����o p��s-colheita de abacaxi 'P��rola' colhido no est��dio de matura����o pintado associando-se refrigera����o e atmosfera modificada

Estudou-se a manuten����o da qualidade do abacaxi 'P��rola', utilizando-se de refrigera����o e atmosfera modificada. Os frutos foram armazenados em ambiente com controle de temperatura a 8��C e 90%UR, durante 17 dias, quando foram transferidos para condi����o de ambiente (25��C, 75-80%UR). Eles foram avaliados na recep����o, caracterizando-os, ap��s 5; 9; 13 e 17 dias sob refrigera����o, e depois de transferidos para as condi����es de ambiente, aos 21; 25 e 29 dias. O delineamento experimental utilizado foi o inteiramente casualizado, em esquema fatorial (6 x 8), tendo-se seis tratamentos (testemunha, duas ceras e tr��s filmes pl��sticos) e oito ��pocas de avalia����o. Os frutos foram avaliados quanto �� colora����o, ocorr��ncia de podrid��es e de escurecimento interno, e a polpa avaliada quanto ao pH e aos teores de s��lidos sol��veis totais (SST), acidez total titul��vel (ATT), ��cido asc��rbico e a����cares sol��veis, totais e redutores. Durante o armazenamento, observaram-se o amarelecimento dos frutos, o aumento no pH, na rela����o SST/ATT, e nos teores de a����cares sol��veis, totais e redutores, que foram maiores ap��s a transfer��ncia dos frutos para o ambiente. Os sintomas de inj��ria por chilling aumentaram com o tempo de armazenamento. Os tratamentos que modificam a atmosfera (embalagens e ceras) n��o influenciam significativamente nos principais atributos de qualidade do abacaxi 'P��rola', mas o uso de embalagem com PEBD e PVC atrasou o aparecimento de sintomas de escurecimento interno ap��s a transfer��ncia dos frutos para a condi����o ambiente. Os frutos sem embalagem e os tratados com cera mostraram-se mais sens��veis �� inj��ria por chilling, que se manifestou aos quatro dias ap��s a remo����o para o ambiente. A embalagem em PEBD e PVC retardou o aparecimento dos primeiros sintomas, em quatro dias.

Comportamento p��s-colheita de caquis cv. Fuyu, atrav��s da atmosfera modificada passiva e da adsor����o de etileno, armazenados sob refrigera����o

O trabalho foi realizado no Departamento de Ci��ncia e Tecnologia Agroindustrial, da UFPel/Pelotas, com o objetivo de avaliar a utiliza����o de embalagens de polietileno de baixa densidade (PEBD) e do adsorvedor de etileno em caquis cv. Fuyu. Na safra de 2000-2001, os frutos foram armazenados a granel, em embalagens de PEBD de 0,022 mm contendo doze e 40 frutos e em embalagens de PEBD de 0,033 mm contendo doze frutos, sendo que apenas metade das embalagens possu��a o sach�� adsorvedor de etileno. de acordo com as vari��veis analisadas (dist��rbios fisiol��gicos, concentra����o/produ����o de CO2 e etileno), os frutos acondicionados nas embalagens de 0,022 mm contendo doze frutos, com e sem o adsorvedor, apresentavam-se em est��dio menos avan��ado de amadurecimento e com qualidade superior aos demais tratamentos. J�� na safra de 2001 - 2002, sob os mesmos par��metros avaliados no ano anterior, foram testados o armazenamento a granel e o armazenamento em embalagens de PEBD de 0,022 mm, contendo doze, dezoito e 24 frutos, tamb��m com e sem a utiliza����o de sach�� adsorvedor de etileno. Ap��s 90 dias de armazenamento refrigerado (AR), mais os cinco dias de simula����o de comercializa����o, os frutos acondicionados nas embalagens de 0,022 mm, contendo doze e dezoito frutos, independentemente do sistema de adsor����o de etileno, apresentaram os melhores resultados em todas as vari��veis testadas.